Printed this TankTarp without the crosses as a weekend hobby paint project.
First I applied a base cover with a sand colored primer (Vallejo 73.614 Sand Grey), painted the drums in white / green (Vallejo 70.820 Off-White / 70.970 Deep Green). Next I applied a layer of woodglue and used fine real sand to cover the base.
After a few hours of drying, I dyed the sand with a mixture of darker sand colors (all Vallejo ModelColor paint) and rough sand was glued to the base to add more "rocks". Again after a few hours of drying, I used superglue (gel which is slowly drying when not in contact with something) to mark ares where I wanted to make grass tuffs and using Busch ModelBau (NOCH) grass fibers (yellow / green) with a home made electrostatic "Grass-Master" (from a electric flyswatter) I added them to the base. Then I drilling a few hols (1.2mm) in the based as a place holder for Woodland Scenics field grass (Gold) which I bundled and glued with superglue to make long grass tuffs.
Added 0.6mm bullet holes in the drums (hey its Warhamer 40k) and painted the holes black and used a dark gray wash (Vallejo 70.517) to create "oil spill" on the drums and also on the ground.
After that I applied multiple layers of dry-brushing with variouse Vallejo ModelColor paints to add dirt on the rocks and dirt and rust on the drums. I finished with a Vallejo "light-rust" wash 76.506 for the finishing touch on the drums and ground.