These tips may not work for every individual student, but they do work for many students. Try incorporating at least some of these into your approach to your courses. They should help most of the time.

1. GET INTERESTED! If you allow yourself to be disinterested in the material, you will probably not do well in the course. Give the course a chance. The higher your interest level, the higher your grade will likely be. Remember that science is based largely on curiosity. If you are not curious about your chosen discipline (especially if it is science) and have no real desire to learn the material in your discipline, you would do well to consider changing majors.
2. AIM for the A! You might make it. If you aim for a C, it's likely that a C is the best you will attain.
3. ATTEND CLASS and be on time. There is typically no surer way to fail a course than to miss class repeatedly, even if there is no attendance policy. Even missing the first 5 minutes of a class can put you into a state of confusion for the rest of the lecture.
4. SIT toward the front of the room if possible so that you can see and hear better with fewer distractions.
5. PLAN & MANAGE YOUR TIME WISELY!If you are full-time student, school should be your top priority in terms of commitment. Taking 15 hours of university credit should require a minimum of 30-35 hours of your time weekly if you are striving to maintain a good GPA. Learning requires work on your part outside of class.
6. LISTEN & try to UNDERSTAND the lecture/presentation as it occurs, and ask questions when necessary to stay with the instructor and class. Don't memorize material without understanding what it means. Only though understanding will you retain the information and be able to use it effectively during exams.
7. TAKE GOOD NOTES: Hard to explain how, as it is something of an individual "art". You should be taking down all the important information and/or highlighting it in your textbook. If you are really listening (point 6 above), you will better recognize what is and, just as importantly, what is not important. You might try taking notes in 2-3 colors of ink, using one color for headings, numbered items, etc. Use red or yellow to underline terms on which you need to work. Studying from page after page of notes in only blue or black ink can be monotonous and allow you to drift away more easily. Don't crowd your notes! Notebook paper is cheap. Leave side margins for making notes to yourself later. Make your notes a "pleasure" to study from. Notes in outline form are easier to study from.
8. REVIEW YOUR NOTES later the same day, on a regular basis. Rewrite your notes if necessary to make them neater, less crowded and better organized. This is an excellent and proven way to learn the material. Some students word process their notes and even add in figures! At least you should make a separate vocabulary list of difficult terms and their definitions, or possibly a set of vocabulary study cards with one term per card.
9. Get your questions answered when they arise, not days or weeks later. Approach your professor if you need individual help, but always have a few definite questions ready to ask him/her (write them down so you don't forget them). Try to think about what your problems are before you visit your professor.
10. Start studying 3-4 nights before an exam date. Don't cram all night the night before. Try to be relaxed and comfortable while studying and avoid distractions. Have some light snacks during your session and/or take short breaks every 40 minutes or so. Possibly use group study if some friends are interested (but be sure you're all there to work!). Don't stop studying when you think you have just mastered the material. Study more to firmly fix the material in your memory. If you have taken tip 8 (above) to heart, your study will largely be review of material you already know fairly well.
11. Keep up with your assigned readings, but don't study from the text unless your professor teaches from the text. When the text references a figure, stop and look at that figure, read the caption, and try to "figure" it out. Remember the saying "a picture is worth a thousand words"? Often understanding the figure will help greatly in understanding the reading, and allow you to remember the material much better. Reading will greatly add to your understanding of the material. Don't be afraid to highlight and underline important words and sentences in the text. Serious readers often do just that, as well as making notes in the margins when helpful. Also, remember that you have an excellent library available with additional resources and quite study areas.
12. Visualize: In Biology especially, and probably in some other disciplines, you need to work on your ability to visualize things. In science we mainly deal with real physical things. Even if those things are invisible bacteria or molecules, they can still be drawn or cartooned, and having mental images of such things always helps one to understand them better, to have a "feel" for the subject. Most science books are filled with figures for that very reason. We need to picture and visualize many of these "things" and processes to aid in our understanding. The more you develop this skill, the more you will be able to master scientific material.

Exam Taking:

1. In the hour before the exam, don't do any serious studying, as this should already have been done. Just take a last leisurely look at a couple of concepts or facts that you may still not have completely straight. Don't start listening to what other students are discussing concerning the material. They may not know the material as well as you, and they may even be saying things that are wrong. At this time you need to be confident that you know the material well, and not be sidetracked by doubt.
2. Go through an exam three times. On the first time through, answer only those questions you are confident of. Waste no time on any question which would require even a minute of thought. The second time through is for those questions that require a bit of thinking, comparison, etc. The final time through is for those few questions for which you really don't have a clue. Give these last questions some thought and make your best guess. This plan will keep you from losing your momentum and confidence, something you most surely don't want to do, especially if the exam is long and time could be a problem. If you use this method, you will often find that on the second reading the answers to some of the questions you skipped earlier will come to you, and you will wonder why you didn't know it the first time. You brain actually works on some of these questions subconsciously while you are working on other parts of the exam--Really!
3. Don't leave anything blank--especially on multiple choice questions. Look over the exam in the last few minutes; the answers to some questions might be found elsewhere on the exam (and spelled correctly too!)
4. Don't change your answers unless you are sure you need to. Your first impulse is usually correct.
5. On discussion questions, think out what you are going to say BEFORE you start writing. Otherwise, you may end up writing a lot but saying little. Don't repeat the question in your answer. Read you answer once you think it's finished. Does it say what you wanted? More importantly, does it answer the question asked?
6. On definition questions, remember what a definition is. An example of the term is not a definition, though it may help to show that you understand the concept.
7. Read all questions carefully. Be sure you know what is being stated and asked. Note especially any qualifier words such as: usually, most, not, always, etc. If you are asked to compare and contrast two items, you must state not just the qualities of one, but the similar or differing qualities of the other as well.
8. Review and check you graded exams carefully; professors do sometimes make mistakes in grading. Look at your missed answers and try to figure out exactly why your answer is wrong, and why you missed it. This will help you avoid similar mistakes on future exams. (didn't read the question carefully, didn't take complete notes, didn't do the assigned reading, didn't study long enough, carelessness, etc.).
9. Keep all your exams until the course is over. They can help you in studying if there is a comprehensive final. They can also remind you of your professor's testing style. In very rare cases, the professor may not have recorded an exam grade. If you have the exam in hand with his/her grading marks on the exam, you have proof that you did take that exam.