Start by watching watching chad's videos for ochem and do the quizes. Next, spend a few days memorizing products and reactants for the reactions in his reaction sheets. (The reaction sheets are separate from the video notes, I think they're about 10 pages long.) Finally, go through DAT Destroyers problems and the roadmaps to learn the different scenarios and exceptions associated with what Chad teaches you.
EDIT: Just realized I basically said the same thing as gangazi XD