l have no clue wat to use

sand

thick paint, and drag something over it, mesh, glass, papper, sand, cloth and paint over, dirt, sticks, you could sew on it if its on paper or canvas.

coins, plaster, sand, beads, crayons, pens.

If your are using acrylics, try drywall topping compound in small amounts, crumbled Styrofoam, crush nut shells, plastic mesh bags, or my favorite, vinyl concrete patch from the hardware store. Use a medium like modeling paste, matte medium, etc to add body to any one or combination of these, or just with the paint. Use same to paste cardboard, papers, newsprint, etc. then paint over them, leaving some areas exposed.or not.