Jinny Beyer has some classes on this. I think the one I saw was on The Quilt Show (TQS), which is a membership online show. It's well worth it tho, they have a lot of information on there, with a new show each week. TQS also has a color class, "Special Effects with Color" which gives you a lesson each week to make a paste up block on paper with your colors choices. That was helpful for me. Christine Barnes teaches that. There's also many books available with color combinations to pick from, check your library.