color flat,need gloss

i've been trying to photoshop my wifes car and i've got pretty good at it.the only thing i'm having trouble with is when i change the color it comes out looking like a flat color.what do i need to do to make it look shiney or wet?i'm using the regular photoshop cs.

set the layer type to "color" and it will show through to the old paint and reflections, then you can adjust hue and saturation.

sweet! thanks