Basecoat the whole model in Retributor Armour alternatively use the Spray
Use a medium layer brush and water down Blood Angels Red slightly. Make sure you don't overload the brush. Carefully paint individual panels - in contrast to normal contrast (no pun intended) painting, make sure that the color does not pool anyway (except deep recesses where its fine), otherwise you have bloody surfaces. The goal is to have a reddish hue on top of the metallic gold. Depending on how thick you manage the first layer you might want to apply a second one for a deeper red. As always rather start out too thin than to thick, it's always easy to add more but not to remove.
