Basecoat, basecoat, basecoat. If you are not able to get that right, you'll never, ever get a good looking model. shading, highlighting, washing, glazing, they all boil down to haveing a solid, clean basecoat that is not patchy and remains detailed.
Choice of pallet is another thing. Bright, vibrant colors are a lot harder to do. Reds, whites and yellows are notoriously bad covering pigments. If you do want to learn how to do solid basecoats, practice with yellow. If you can get a none patchy, thin, even basecoat going with yellow, you are golden! Heck, you can even try that one piece of sprue or a leftover torso from a space marine set or something.