^^ When I do colors I try to get a saddle pad in my main color (royal blue in your case) with a trim in my second color. For me its navy with a light blue trim! I wear a light blue shirt and My boots jumping boots are light blue! With a black xc vest.
Last year my colors were black and pink and my saddle pad was a cow print :) But this year I think I'm going to do green and black and just have a black saddle pad with green trim, I'm not sure though. Three out of the Four other eventers at my barn have light blue and dark blue as their colors, it's a very popular combo