1. Start with your lecture notes. If you have followed my suggestions about taking good lecture notes, then you will probably have a goodinfrastructure with which to begin working with your subject.
2. Read your textbook for understanding. Take the textbook that is prescribed reading for your course and read the relevant section for understanding, not necessarily for memorizing. Read the section with highlighters, pencils and a notebook at hand for you to jot down any questions you have. Remember, you are reading to understand, so memorizing you are going to leave for a later stage. This particular step is fit for a whole series of topics all on its own, and perhaps we can delve into that in the near future.
3. Read other textbooks. Here, find books that simplify the information. A medical example would be Human Anatomy For Dummies. These books will often break down the information into understandable chunks and explain it in such a way that you can immediately grasp and begin to apply.
4. Seek out knowledgeable students.Take note of those in your class who seem to be pretty clued up on what is going on in the course you are struggling with. If you have a good relationship with them, approach them and ask them if they wouldn't mind explaining some of the key concepts to you, and perhaps showing you how they approach studying the subject. You don't need to even find a student on your own class, you could find one who is a year or two ahead of you who you know did well in that particular subject. Again, offer to buy them a cup of coffee, spend time with them and absorb information like a sponge.
5. Speak to your lecturer. Some lecturers are simply on another planet and cannot be reached by any conventional means. In this case, see point number 3! However, fairly frequently, lecturers are quite willing to spend time helping you if they can see you are struggling with their subject. Make an initial appointment, prepare what you are going to ask them, bring all your books and notes along, and then grill them!