10 ways to make organic chemistry easy

Here are ten tried and true ways to keep organic chemistry from being the headache it is for so many students. With these (and some enthusiasm) you might start to see the beauty of the subject for what it really is.

1. Always draw out mechanisms. Draw out mechanisms for every step of your retrosynthesis, even though you don't have to do so to answer the question. You'll never forget another mechanism, and you'll get a much more intuitive understanding for generalizations of the chemistry.
2. Don't worry about the hypothetical lab chemist you're directing in your retrosynthesis. It's possible that the path that you pick requires him to run five columns; that doesn't matter. What's important is that your chosen sequence of reactions works, and never mind the yield.
3. Categorize reactions by the type of bonds they make and the type of reagents (acids? bases? organometallic catalysts?) they require.
4. Make a notecard of protecting groups and the conditions required to install them and remove them.
5. In retrosynthesis, draw out trial disconnections across any bond type that you know how to make. If you're given fragments you must include in the synthesis, draw out every pattern that could have those fragments included (this is a lot if the fragments have only two to four carbons, and very few if they have a dozen). This is exhausting work, but as long as you haven't forgotten a reaction you've learned about, you'll get the question right eventually. Over time, you'll be able to eliminate less feasible patterns on sight, to the point that you need to consider seriously many fewer trial disconnections.
6. Determine what functionalities in given fragments must necessarily be included in the product. If a given fragment has a carbonyl unit, remember that that oxygen (or any other heteroatom there) might not appear in the final product if there's any chance the Wittig reaction would come in handy.
7. To practice mechanism questions, pick a named reaction at random from http://organic-chemistry.org/ or http://en.wikipedia.org/Named_reactions. You haven't learned it, but see if you can guess at the underlying chemistry? Generally the mechanism will be given on at least one of those sites, so you'll have something to check against.
8. For box problems, make sure the final product you drew isn't sensitive to the reaction conditions. For example, if you draw a product that has an ester hydroxylated somewhere, and it's in a rather acidic or basic solution as of the reaction's last step, how do you know it won't cyclize? (Hint: it very well might.)
9. If you're stuck on a retrosynthesis problem, do another one. In solving the second, you might discover an absolutely canonical sequence of reactions that you could apply to solve the first.
10. Work really hard. You won't gain an intuition for how a complex reaction or series of reactions works until you do many problems involving it. Work REALLY hard.