beginner seeking advice on colors

[StevenKnot]

Hi,

i am fairly new to painting-i have only oil paints-and am having trouble
mixing colors-whenever i try to mix let's say, white with ultramarine blue,
trying to get a sky blue effect, my color comes out much too dark-which
facilitates me having to add a tremendous amount of white, wasting much of my
oils-i would appreciate any advice anyone would have on mixing colors, or even
in oil painting in general-have never had a lesson, just been something i've
always wanted to do, so went out and bought some supplies-having some trouble
getting depth to my works

because i don't check newsgroups as often as i check my mail, i would
appreciate any responses be mailed to me at this address

thanks,
steven.