Thanks! My technique was - prime with Army painter dark red (chaos red I think it's called) which gives a nice red-brown to start with. Then it was all Vallejo paints; Sand Yellow and Sand Ivory to pick out rocks, sometimes I dry brushed detail on top of the brown primer, other times I'll paint a rock solid with that shade then dry brush with a lighter tone by mixing in some silver grey, which I also use for the highlights. Basically I went for lots of variation in the colors of individual rocks, but all from the same limited color palette. I used Carne Flesh Wash for the pinky red hues and Sepia Wash for yellowy brown to color individual rock hues and areas of the rocks as well. Real life rocks always have loads of color variation across them. Always tried to stick to darker hues in shadow areas, bottom half of rocks etc.
I really love that sepia wash for Tattooine stuff, probably the desert equivalent of everyone's standby Agrax Earthshade, I use it for loads of stuff :)
I'm also a big fan of Vallejo's Desert Sand texture paste, costs about £9 (UK) for a 200ml tub which just seems to keep on going and going! Really recommend it, well worth the money; I use that on the MDF bases and spotted around to texture up areas of the styrofoam and to fill gaps to give the sand texture. It looks better to me than dipping in sand and painting, more sculpt-able. That has a very yellowy sand tone, so that's adding to the overall mix as well in places. Pretty easy to work it once it's on the base as well, it's great for texture. Finally I stuck all the tufts, cork scatter, and my fingers to the base with super glue. :)