you have to make them up for your repaints white for non reflective parts and grey for the parts you want to have the gloss look on
the darker the gray the more it shines

but word of advise start with the lighter grays first and see what you like and don't go over 50% gray it looks nasty

also when you get more time spec and spec_alphas can help with some good effects but only if the aircraft you are painting uses them

there is a lot of trial and error in making the alpha just right when you first start painting stick at it have fun and if you get stuck some one here will help out