For
BA, there are two sytles that look really good.
Either you can go dark, using a black basecoat and then darker reds like Khorne red > Wadakka red and then a highlight of mephiston red, or you can go for a lighter tone more like the
GW one with a base of black or white (I prefer black on the whole) and then go Mephiston red > Evil Suns Scarlet > Wild Rider red. This last one can be found as a paint bundle here:
http://www.games-workshop.com/gws/catalog/paintChart.jsp?catId=cat820002a&rootCatGameStyle=paints-tools
Either way, I'd do the non-armour parts base black, drybrush boltgun metal, drybrush chainmail to get a metallic look. I also do the bolter casing black. A wash of either Nuln oil or Agrax Earthshade will help massively with shading whichever you go with. I prefer the darker scheme myself, but this is just preference as you can do a lot more with washes and not so many layers. For lighter schemes, layers and edga highlights are far more important.