Here is one of my monsters with painted texture:
I decided to see if there was another way I could get a nice texture without it taking so long. I started to play around with painted colours on watercolour paper and then scan them into photoshop:
I then brought a texture square into a picture I was working on in photoshop and overlaid it on top of a layer that contained the shape of my monster, cut it out to fit the shape using the magic wand tool and then I just lowered the opacity so that it blended with the colour of the shape underneath:
I could then still add shadow and highlights on top and the monsters started to look a lot rougher and monster like. The final result ended up looking a lot like this:
I will continue to experiment with different textures, using anything I can find and rubbing it on paper and playing with it in photoshop. I think the way to go with this is to just be rougher and quicker with these pictures, sticking to bold shapes and simple staging.