I recently bought myself some 54mm plastic toys soldiers by Armies in Plastic via the Toy Soldier Company and Regal Toy Soldiers and I'm not quite sure how I'll go about painting them. The only firm decision I've made is that they'll be gloss varnished, because toy soldiers have to be all glossy. That's just a hard physical rule of the universe.
These ones are modelled on British infantry in Egypt and the Sudan in the 1880s.
Option one (the top photo) is the more toy-like method. I've done a bit of outlining, which goes against the Pure Toy Soldier aesthetic I suppose, but I felt it needed just a bit more definition than a simple flat paint job could provide.
Option two (the lower image) is in a more modern wargames tabletop-quality style, though simplified a bit. Three tones — shadow, mid-tone and highlight — to give the figure a bit more depth and modelling. It does look a bit less toy soldierish, and it also takes a bit more time than the simpler paint job, but I think I'll probably go that way.
The gloss varnish does tend to blow out the highlights in the photographs; I'm not quite sure how to remedy that. Hey-ho, on the scale of things that's a pretty small problem.