One of the key breakthroughs of my new "Emperor's Children" army project has been the use of an oil wash over the whole model after the acrylics to make them more battle-worn without worrying about the usual darkening of a paint scheme that is associated with "dipping". Aside from the terrible smell of white spirits (turpentine) the oil wash has many benefits as it can be manipulated for many hours after applying, does not affect the overall finish of the paint scheme (no shiny residue once dry), and is very cheap when compared to acrylic washes or similar products.
Aside from the terrible photos (which have both had an "auto white balance" applied to them) you can see the effect most noticeably on the cloth sections of the model and the base, both of which gain extra depth and lose some of their glare which detracts from the overall colour scheme. The gold on the left has been shaded only with an acrylic purple wash (after the two gold colours where applied and re-touched), then the whole model coated in GW's Lamium medium before the oils are applied. I used a hair dyer on the first few models to speed things up, but now have a dedicated drying container to keep the smell in and the cat out!