The first, and arguably the most important, study habit is recognizing that you are responsible for your successes and also your failures. Taking on this responsibility entails the understanding that your priorities, decisions, habits, and resources all determine the success you have, or do not have, with studying. This responsibility carries over to the friends, family, and acquaintances you choose to surround yourself. Having a clear sense of who you are, including your beliefs and values, instead of letting others dictate what you say, do, and believe, will also help you to be more successful on the path you choose.
Next, you need to establish your goal. What is it that you are trying to accomplish through studying? What is motivating you? After these questions are answered, you can better arrange your priorities in order to be successful at reaching your goal. Remember, your goal and priorities should be dictated by you, not by the people who surround you.
Finding the times and places when and where you do the best work is essential to being successful and reaching your goals. Are you more alert in the morning or the early evening? This will help you decide when you should schedule study time. Also, make sure you have a room or quiet place that is set up for studying. It should be free from distractions, climate-controlled, and hold everything you need to have an effective study session (a calculator, a ruler, textbooks, notebooks, a dictionary, computer, etc.).
Sometimes the grade received on a project, a test, or for an entire class does not always reflect how well you feel you performed on the task. Try to understand that the first check of your success should be if you feel you gave your absolute best in class, on homework, on quizzes and tests, to the other students, and to the teacher. If so, then you succeeded, despite what the grade you received...