dont use different colors

use transperency

put a base coat then take that red and make it darker. lower the opacity/transparency and do one layer with a little red showin and then another layer that is a little smaller than the last and smaller and smaller and smaller. By layer i dont mean add another layer just put the transperent red and layer it on top

hope you take my advice

oh and I want you to know something..... read this -------> I commented and gave you the answer

I can I like right