My studying philosophy is that I need to understand the fundamentals behind a concept like why something is a certain way and not another way, and what causes things to be different or similar. Eventually, when you understand those fundamentals, everything else falls into place and just makes sense. So-called exceptions to various rules are really just nuances with very good reasons for being so. I aim to understand something to the point its as obvious as 1+1=2. This approach takes time but will put you on the path to mastery and help you retain information for much longer.
For organic chemistry, I found it helpful to understand how the structure of a reactant contributes to its reactivity. Eventually, it just became intuitive and I could work through questions very quickly. Eventually, you will recognize common patterns of reactivity centered around electrophiles reacting with nucleophiles. Many reactions are really variations of each other. Some look similar while others look dissimilar but are actually following common patterns. I found this study strategy very painless compared to pure rote memorization.
For general chemistry, I did not encounter any major calculations. I don't have anything to suggest other than practice more and focus on understanding exactly why certain solution steps need to be taken. When studying, I was really obsessive about figuring that out.
