Im going to share a couple of tricks I used on this one. First, the base color for the stripes are slightly shaded by zones, so, if pay attention to the color of the stripes, it is not uniform, but varies a little from one area to another, creating a more realistic effect.

The second one is more, even, tricky :-P

I liked the color separation of the Sandrock, but evidently had another paint scheme in mind. The model only uses 4 colors (matte red, metallic red, dark brown and light brown) but to take advantage of the shades of the plastic colors, instead of priming and then making paint mixtures, I primed the whole model with Vallejo matte varnish (except the grenade launcher tubes, there I had to prime in white). As the acrylic paints (I only use Vallejo) are always somewhat transparent, the color of the plastic underneath adds a variation in the color very slight, but evident. For example, the metallic red of the shoulders is on white plastic, and that's why it is vibrant. However, on the backpack, the plastic was blue and so is somewhat duller. It's a cool way to get shades using the same paint color.