Heres a general idea of what I've learned are the most common beginning mods.
Free Mods here,
www.installuniversity.com
1.Lid
2.ORY
3.Cat-back exhaust or True Duels<--personal prefference between those two, depends on how loud you want your car.
4. Headers
5. Cut-out if you go with cat-back.
6.Port and polish your throttle body/or buy bigger one.
Those are in no certain order by the way. Just what I could think of off the top of my head. Hope that gives you an idea.
Someone else feel free to chime in......