Use the colour wheel as the basis for a single colourfull illuration that could be tessellated across the wrapping paper? color theory chart - beautifully simply way to learn this (plus the fact that I suck at combining colors LOL!
Artists and design experts know that triad colours work together in harmony. Triad colour scheme works by showing people the opposite colours on the wheel work together to make all the colours stand out. But not the base colours