The figures are good, maybe some lighter areas on the faces, nose, cheeks, forehead, to make them stand out more.
As already stated, your bases are the weak point. Try painting all the base in an earthy colour, including the edges, then use fine grit and gravel to cover it. Paint this in earth tones, then drybrush lighter browns on. Top this with scatter foliage and grass tufts and they will be much improved.