What to get:
1) Improve your Driving Skills(It's 90% driver and 10% car)
2) Built 2ZR or engine swap(cams, tune, etc.)
3) Transmission upgrades(short shifter, LSD, etc.)
4) Suspension Upgrades(coilovers, strut bars, etc.)
5) Weight Loss(Replace with carbon fiber parts)
What to stay away from:
1) Rice stickers(Flame stickers, Chevy badge on your car...)
2) Being a showoff(Don't be a stupid child while driving)
3) Fartcans(Install a proper exhaust system and not a food can)
4) Big Spoilers(Your driving a FWD car, not a Plane)
5) Trying to "fit in"(Mod your car however you like, it's your car, not ours)
Even though most people say that they are just Corolla's think that they are not worth modding, you can do anything with time, money, and attitiude. If you want to mod, I would say start small like lowered springs, intake, etc. and work your way up and see how each mod affects the car. This is how you learn and this is how you have fun in life.