How to study hard and effectively
First of all, you need about two hours of study time per hour of lecture in college. Of course, this is just an average. If you are taking Math 55 at Harvard, you may spend 40 hours a week just on problem sets alone. In junior college classes, you may get by on 30 minutes of studying per hour of lecture. But, on average, a 3 unit or credit class load implies up to 6 hours of studying per week in addition to the 3 hours of lecture. Studying hard is worth the effort though: post college wages are positively correlated with study time in college.  An hour of studying is defined as 45 to 50 minutes of undisturbed concentration followed by 10 to 15 minute break of physical activity such as walking.  
Mental activity burns a lot of glucose, exactly like endurance sports. Keep blood sugar available to your brain by ingesting a small amount of glucose as needed.  Ideal snacks that provide glucose are baby carrots, apple slices, and nuts. Avoid dried fruit unless you can brush your teeth afterwards. If food is not allowed where you study, try using the glucose tablets used by diabetics.
Avoid eating a diet that regularly includes added fructose without fiber such as soft drinks and candy. Researchers have found that a sustained diet high in free fructose slows the brain down and negatively affects memory and learning.  Consumption of Omega-3 fatty acid seems to counteract the effect, but only partially. The effect is striking. Rats fed a diet high in free fructose and low in Omega-3 fatty acids took nearly 5 times as long to remember a task they had learned 6 weeks earlier compared to rats on a healthy diet.
If possible, study in hour long chunks in the morning and in the afternoon instead of one long time period to take advantage of the spacing effect.  Avoid studying in bits of time less than one hour throughout the day. When you draw up a schedule for yourself, pencil in the lectures, and then one hour (minimum) blocks of time for studying. Then add everything else.
Always study in a quiet location free of visual distractions. Noise of any kind, whether rhythmic music or random background noise, has repeatedly been shown to have a negative effect on learning and retention.  Memory recall has been found to be significantly better when distractions were minimized. If you are forced to study in a noisy environment, it might be wise to wear noise cancelling headphones or ear plugs. Memory “athletes” wear ear plugs under head phones plus goggles that are blacked out except for two small holes to minimize distractions. 
Don’t always study in the same location. Strangely, alternating the room where you study dramatically improves retention. So does studying different but related skills or concepts in one time chunk, rather than focusing only on a single subject. In a single 45-50 minute study block, you will retain more if you study two related subjects than if you focus on a single subject. 
Get out of bed early, exercise and don’t hold a job. In one study, of all the variables considered, wake-up times had the largest affect on grade point averages, with later wake-up times being associated with lower average grades. Perhaps because student environments are typically quieter early in the morning and therefore better for studying? Other variables associated with 1st-year (college) students’ higher grade point averages were strength training and study of spiritually oriented material. The number of paid or volunteer hours worked per week was also associated with lower average grades. 
Success in college requires long hours of solitary studying. If you feel socially isolated, take foreign language classes, even if you can test out.  Don’t reject other activities because you want to focus solely on studying. Participation in college sporting activities has been found to help promote college student’s mental health.  And extracurricular activities do matter to employers. Employers tend to hire people who are similar to themselves in terms of preferences. They may assume a lack of involvement is a sign of social deficiencies. So, strangely enough, membership in a professional engineering society is seen by some employers as padding the resume, while involvement with the tennis team or the ballroom dancing club is seen as evidence that a person is fun to be around and has strong social skills. 
Limit the time you spend surfing on the internet for fun or playing computer games by yourself. Non-heavy internet users have been found to have better relationships with their instructors, academic grades, and learning satisfaction than heavy users. Heavy users are more likely to be depressed, physically ill, lonely, and introverted. 
Write down as many notes as possible during class, even if notes are provided. Typing your notes during lectures may be slightly beneficial versus writing by hand.  If you have a question or need clarification during a lecture, make a note of it. Be sure to raise the question either during the lecture or afterwards.
Study your notes by neatly re-writing them as soon as possible after class in a quiet place free of distractions (preferably that evening, but never wait more than 24 hours). As you re-write the notes, imagine that you are giving a lecture to a class and give a full, coherent explanation – from the big picture to the tiny details – of every topic covered by the notes. Let your imaginary class ask you tough questions about your lecture. If you can’t answer a question, bring it up at the next lecture.
Study your more difficult subjects first because you will have more energy.
You will typically want to read your reading assignments or textbook slowly for comprehension, although, if studying literature, you may want to read through it quickly the first time. Study by reading the text, then set the text down, close you eyes,  and recite all that you can remember either out loud or silently, or imagine you are giving a lecture on the material, and then read the text a second time to review. Do this a few times until you are confident you completely understand the material, and repeat 24 hours later and then again within 24 hours of your test.
If you are using a textbook with end of chapter questions or problems, quiz yourself on the questions at the end of the chapter before reading the chapter. You won’t be able to answer many of them, but this isn’t the goal. What this does is focus your attention on the critical concepts as you read. 
For homework exercises or problem sets, do a rough draft and then copy the results neatly on another sheet to hand in. Keep the draft in case the copy submitted is lost by your instructor.
You will learn more from repeated self-testing than from repeated reviewing. Self-testing forces you to accept the fact that you didn’t remember something, while just reviewing material can fool you into thinking “Yeah, I know all this stuff”. 
- For subjects which have essay tests, make up some plausible essay questions, or get copies of old exams that have essay questions on them and write sample essays.
- For subjects that have problem solving or proof tests, put together a collection of exercises or questions that might be asked on an exam.
- Solve/write these individually and then review your answers/essays in a study group of no more than 4 or 5 similarly motivated people for 2 hours per week.  If a study group is out of the question, many classes have on-line bulletin boards where you can post and view others answers.
Review the material you are attempting to commit to memory just before you go to sleep and test yourself on it the following day. There is compelling evidence that the long-term storage of memories primarily occurs while we are asleep, but only if we expect to need the memory. The mere expectancy that a memory will be needed in a future test determines whether sleep significantly helps retain this memory and it produces a strong improvement in retrieval. 
Advertisement – Article continues below
Treat every test, quiz and homework assignment as if it was terribly important. Students who felt an exam was useful and important put in more effort and consequently scored higher than students who thought otherwise.  Self-talk such as “This quiz is stupid” will predictably lower your scores.
You are ready for a test when you have over-learned the material roughly 24 hours before the test. Crammed knowledge will dissipate over time, however.  To retain the knowledge longer term, for qualifying or professional exams or foreign language study for example, you will need to continue to self-test yourself on the material periodically. You may find a memorization scheduling software application helpful. Supermemo has low cost or free versions available for PC users. Genius is available for Mac users.
- Clues from your professor on what might be on a test can sometimes save you days of studying, especially for final exams, so don’t be shy about asking if such-and-such will be on the test.
- Don’t hide academic problems; ask for help quickly. If you don’t, you may spiral downward very quickly.
- Don’t compete with other students for grades if you find it stressful, just focus on learning the material.
- Take a bottle of water with you when you take your exams. Students who brought water into exams were found to have higher test scores, possibly because they were keeping hydrated.
Related external links
 P. Babcock, M. Marks, Leisure College, USA: The Decline in Student Study Time, American Enterprise Institute, No. 7, August 2010
 Healy GN, Dunstan DW, Salmon J, Cerin E, Shaw JE, Zimmet PZ, Owen N., Breaks in sedentary time: beneficial associations with metabolic risk, Diabetes Care. 2008 Apr;31(4):661-6. Epub 2008 Feb 5.
 T. Warren, B. Vaughn, S. Hooker, X. Sui, T. Church, S. Blair, Sedentary Behaviors Increase Risk of Cardiovascular Disease Mortality in Men, Medicine & Science in Sports & Exercise: May 2010, Volume 42, Issue 5, pp 879-885
 D. Kahneman, Thinking, Fast and Slow, Farrar, Straus and Giroux, 2011, pp 42-44
J. M. Murphy, Relationship Between Hunger and Psychosocial Functioning in Low-Income American Children, Journal of the American Academy of Child & Adolescent Psychiatry
Volume 37, Issue 2, Pages 163-170, February 1998
 D. Rohrer, H. Pashler, Increasing Retention Without Increasing Study Time, Current Directions in Psychological Science, Volume 16 Number 4, 2007 [pdf]
 Krýsa I., The effect of noise on learning and retention, Act Nerv Super (Praha). 1983 Dec;25(4):299-303.
 B. Carey, Forget What You Know About Good Study Habits, The New York Times, Sept. 6, 2010
 M. Trockel, M. Barnes & D. Egget, Health-Related Variables and Academic Performance Among First-Year College Students: Implications for Sleep and Other Behaviors, Journal of American College Health, Volume 49, Issue 3, 2000
 K. Zernike, Books: The Harvard Guide to Happiness, The New York Times Archive, April 8, 2001
 F. Wang & Y. Laing, PE’s Role in Promoting College Students’ Mental Health, Advances in Intelligent and Soft Computing, 2012, Volume 117/2012, 729-734
[11.1] B. Caplan, How Elite Firms Hire: The Inside Story, Library of Economics and Liberty, Nov. 18, 2011
[11.2] L. Rivera, Hiring as Cultural Matching:The Case of Elite Professional Service Firms [pdf]
 Y. Chen & S. Peng, University Students’ Internet Use and Its Relationships with Academic Performance, Interpersonal Relationships, Psychosocial Adjustment, and Self-Evaluation, CyberPsychology & Behavior, August 2008, 11(4): 467-469
 A. Vredeveldt, G. Hitch, A. Baddeley, Eyeclosure helps memory by reducing cognitive load and enhancing visualisation, Memory & Cognition, 2011 Oct; 39(7):1253-63.
 H. Roediger & B. Finn, Getting It Wrong: Surprising Tips on How to Learn, Scientific American, October 20, 2009
 P. Belluck, To Really Learn, Quit Studying and Take a Test, The New York Times, Jan. 20, 2011
 M. Boehler, et al, An evaluation of study habits of third-year medical students in a surgical clerkship, The American Journal of Surgery, 181 (2001) 268–271 [pdf]
 I. Wilhelm, Sleep Selectively Enhances Memory Expected to Be of Future Relevance, The Journal of Neuroscience, 2 February 2011, 31(5): 1563-1569
 J. Colea, D. Bergin, T. Whittaker, Predicting student achievement for low stakes tests with effort and task value, Contemporary Educational Psychology, Volume 33, Issue 4, October 2008, Pages 609-624
 J. Driskell, et al, The Effect of Overlearning on Retention, Journal of Applied Psychology, Vol. 77, No. 5, 1992 [pdf]
 R. Agrawal1, F. Gomez-Pinilla, Metabolic syndrome in the brain: deficiency in omega-3 fatty acid exacerbates dysfunctions in insulin receptor signalling and cognition, Journal of Physiology, April 2, 2012
 J. Foer, SECRETS OF A MIND-GAMER How I trained my brain and became a world-class memory athlete, New York Times Magazine, Feb. 15, 2011
 I. Schoen, Effects of Method and Context of Note-taking on Memory: Handwriting versus Typing in Lecture and Textbook-Reading Contexts, 2012. Pitzer Senior Theses. Paper 20.