Hey Obi
Simply prime the minis skull white
Paint them in the colours you like (go a little brighter than usually) - For my minis I used ultramarines blue and blood red for clothing, chainmail for armour and weapons, vermin brown for leather straps and bubonic brown for shafts on the spears.
All feathers I gave a extra layer of skull white.
Hair and beards where done with different shades of grey and brown.
And here comes the "trick":
Dipped or rather brushed them with Army painter Quickshade: Strong Tone thinned down a bit with spirits. Preferably I would have chosen Soft Tone instead for empire but bought Strong Tone as I started out doing an orc army where the darker shade given by Strong Tone looked splendid! But it still works just great with empire when brushed on in more controlled amounts.
And thats pretty much it - Can only say that dipping is the way to do things quick and with a really pleasing result!
Hope it wasn't too much of a trouble to get through.
Btw. Here is an earlier thread of mine where I requested some help choosing colours. There should be some pictures of different minis (empire and Orcs) painted and dipped:
http://www.warhammer-empire.com/theforum/index.php?topic=28471.0SOLID