Coilovers, rims and tires, headlights, lip kit, exhaust, intake, header. Lots of options! It's all about personal preference though. Check out the DIY section for lots of cheap and easy mods to get you started. Happy modding.
I'd start with a tune up, make sure the car actually runs good first. Rubber gaskets and seals also belts dry-rot over time, keep that in mind,so when you "step" on it you won't have oil leaks everywhere or timing belt snaps and there goes your f23 vtec. Your accord should have a little book/maintenance log, check your mileage and see what should've been done, up to now, or go from what previous owner told you good luck
Start in the diy section and go through all the maintenance procedures first. That will help you get familiar with her. After that it really all depends on what you want to get out of her. Tons of parts available in the classifieds.