help with my teeth ! need opinions please !!!?!

ok, my teeth arent yellow, but theyre not paper white either, i want my teeth white as possible.. im starting to brush after EVERY meal, when before it was in the morning and b4 bed. i use mouthwash, just plain regular listerine.. will crest whitestrips work ? i bought some but... ALSO i am going to have to get my teeth straightened here in the next few months... is there anything i can do to build my teeth up stronger, like help the enamel too... i cant drink milk, it makes me sick but i guess i will if thats what i need to do.... i would appreciate someone in the dental fields opinion =]