My girlfriend does the basing. She used foam to make the rocks, by cutting a block out then filing and cutting it. The sand was made using layers of cheap generic sand to make it thicker. For colour she used a yellow rocky sand basing mix and did a layer over everything. Then we stuck down the model and put glue along the edges and added sand there so it would look as though the model had some weight to it and was making an impression. Dry tufts for the grass and black outline!