For me, I was most successful while reading the chapter that was being covered in lecture first--which means I read every single chapter that was covered--but it was veryyyy time consuming. This provided me with a framework of what the chapter was about. I was also actively answering the problems that were provided throughout chapter's sections and would check them with a solution's manual.
I would then do the extra practice problems my next study session (usually the next day) that were at the end of the chapter with the solutions guide next to me when I got stuck. I highly encourage that you try to answer the problem the best that you can before checking to see what the answer is. As ppl have stated above me, it really is all about practice. That means doing organic chemistry every day for several hours. Practice practice practice problems. Keep drawing mechanisms until your hand cramps (lol) and try to see the patterns that occur (for example: nucleophile attacks electrophile)
This is getting specific but if you can develop an intuition with organic then come exam time it will flow. By that I mean, organic chemistry is like a learning a second language. When you become comfortable with a new language the words just start to flow and there isn't much thought in speaking it and conversing. You can't memorize the language; instead you have to learn it. This might not make any sense, but if you can look at the starting material and just feel what reagents are needed to get the products, then you will be good.
I also HIGHLY suggest you chart all the reactions you are exposed to. I divided the reactions up based on chapters because there is a ton of variation and many exceptions. Come exam time, I would have everything compartmentalized so I did not miss any reactions. I also utilized office hours a lot. I would stare at my list of reactions at breakfast, lunch, and dinner on Saturdays and Sundays; this isn't for everyone but it worked for me!
starting material --->reagents ---> end product
This is a lot of info and as you can tell I enjoyed the class. Taking the course is essentially testing your will to want to succeed. If you put the necessary time in, you will succeed. Organic is not inherently difficult, just a lot of meticulous work required.