If you want "fast", I recommend texture paints. You just apply them really thick (around 1mm thick if not more), let them mostly dry, but before they completely dry, attack them with a toothpick or a needle and just stir them up on the base to add a bit more depth.
Then you can just wash, drybrush and apply some grass and it looks pretty good and is super fast.
GW texture paints are massively overpriced. Because you use it so thick, you'll go through several pots to do an army (I used GW ones for my Orcs and Goblins and I think I'd only get about 1 or 2 regiments per pot). However other people sell texture paints a lot cheaper, like Vallejo.