Add decorations

Use rocks, cork, etc for ground decoration.

Cover base with texture paint

Agrellan Badland = rough cracking mud

Agrellan Earth = fine cracking mud

Astrogranite Debris = rough rocks

Armageddon Dunes = rough sand

Paint

1. Stain with something like Dark Tone (or similar), Agrax Earthshade , Mortarion Grime or Biel-Tan Green .

Dry vs wet

1. For drier ground: Dry brush with Arid Earth or similar.
2. For wetter ground: Paint with Gloss Varnish for a wet mud effect, pool drops to create puddles.

Add vegetation

1. Add tufts or similar foliage.

Rim

1. Paint rim in Black .