Organic Chemistry is a very general subject covering a broad range of topics. Therefore, there will be a lot of information pouring at you in very little time. It is important not to fall behind in class and to ask your professor about anything confusing said in lecture class.
In Organic chemistry you need to know the difference between MEMORIZING reactions and UNDERSTANDING them. While the former sounds like the ideal way to get that quick "A", you'll soon realize that the latter is the ONLY way you will succeed. If you understand concepts effectively you will be able to predict expected outcomes in reactions.
When studying for a test, it may be more useful to have several different reliable sources from where you can learn concept from. Chances are your lecture notes won't be as neat as you'd like them, considering professors sometimes forget you are trying to copy the reactions on the board while they are talking about important information.
SN 1, SN 2, and ELimination reactions are VERY important in Organic Chemistry. Make a list of differences between the two reactions. Which one changes chirality? Which has a carbocation intermediate? Which creates double bonds? Under what environments do they occur? Professors LOVE questions involving these reactions.
If you are taking an Organic Chemistry Lab, take advantage of it enhancing your knowledge. Don't just mix chemicals together because the lab book tells you to. There is a reason why people need to learn Organic Chemistry, and it's not just for writing down on a piece of paper. For some people, it is easier to remember something they've done, rather than something they have read. After doing Grignard reactions for example, you'll know why you can't have water left in your flask when making an organometallic compound. Mistakes made in lab can help you remember what NOT to do in a reaction better than any textbook can!
NMR spectroscopy is something many students can find a bit challenging at first. Think of it as a puzzle. To determine the structure of a compound there are some tips and tricks. For instance, count the integration of the hydrogen peaks if it is a proton spectrum. Once you know how many hydrogens there are in the compound and how they are integrated relative to other peaks, you can begin drawing a "skeleton" of the compound. The multiplicities can help tell you how many neighboring hydrogens they have. Practice makes perfect. There are many website solely devoted to NMR spectroscopy.
Whether you need to use ball and stick models or a dry erase board, you'll need to learn to visualize structures. This will be helpful with chirality, chair conformations, and why certain molecules react the way they do. And remember, Organic Chemistry isn't a subject that many people can just understand after one lecture. It takes hard work, and the beginning concepts are the hardest to understand. Once you get it, it can even start to become a piece of cake!