Go to the library and check out a couple of different books on color for quilters. I have learned different things that help me from each book I've tried, although I'm still struggling with color. Jinny Beyer has a good book on color, I forget the name. She doesn't rely on the color wheel. It's out of print, I think, but the library might have it. Even if you don't aspire to make the sort of quilts Jinny makes (which I don't) her ideas on color and shade can be very helpful. THere are some very intersting pictures of the same quilt using exact matching colors of the colors in the focal fabric, and some using a color a shade or two deeper and I think a shade or two lighter than the exact matches as well, and it really makes the quilt pop to have the deeper and lighter colors.
Sometimes the best thing is just to look at what "looks right" together. I tried to pick colors for a quilt using only the color wheel, and I wasn't as happy with those choices as I was with the ones I finally decided on just going by what "looked right" to me. I own "Color for the Terrified QUilter" by Sharon Pederson and someone else, but I haven't actually gone through and done any of the color practice quilts in the book, which might be part of my problem with picking colors by the color wheel.