Apartment Makeover!

Okay so yesterday i painted one side of our apartment wall, with what i think is just white....
I can't believe how many different types of white there are?
 - Whisper white, which supposedly has a tint of green in it. (What we are using)
 - Egg shell white
 - Sand
 - Cream
 - Mascarpone
 - Stone
 - White DARK (Which is pretty much grey...)

 Geeeeee its soo overwhelming =(

Any one have any painting tips for me? like:

E.g "Do NOT use ceiling paint on the walls to try and save money!"