After finishing the sand on top of the bases I then added a combination of flock and static grass with small dabs of PVA (white wood) glue. This glue dries clear so is invisible. After that it was just a matter of giving the base rims a couple of coats of slightly watered down Citadel Bestial Brown paint.
Finally a couple of coats of a matt spray varnish (I use a relatively cheap brand called Cyrstal Kote Matt from a dollar store) and voila! 48 Games Workshop Moria Goblins fully painted!
You can click in the pictures for a larger image.