I need help with color combinations!

[BleeckerSt_Girl]

Well red yellow and blue are the three primary colors. Thus, yellow & blue cannot be any more 'right' than blue & red or red & yellow.
You might be thinking of 'complimentary colors', but for that you need 6 colors: yellow, orange, red, violet, blue, and green....laid out in a color circle. Then you pick the colors directly opposite each other (which you can't do with a simple 3 color primary triangle), such as blue and orange, or green and red...and those are complimentary. The complimentary color to yellow would be violet.