Look at/review the following:
1) Hybridization, double/triple bonds
2) Acid-base reactions (do you remember what Ka is?)
3) Equilibrium (don't need all the math, but you should understand the idea and Le Chatlier's principle)
4) Basic ranking of H, C, O, N, F, Cl, Br, S in terms of their electronegativity
5) Reaction coordinate diagrams (energy diagrams, delta G, activation energy)
I'm not saying you have to know all of this before you start the course... I'm sure you'll go over this stuff again in the class at least as a refresher, if not more in depth. But off the top of my head these are the gen chem ideas that probably are used most in organic class.
Best of luck.