BassinMaumee, Something I did to give me something to practice on or to try a skill out before I apply it on a crank....
I went to Lowes and bought a small/med size piece of latex/polycarbonate sheet (cost about $4) and painted one side w/ white primer. Flip it over and the primer shows through and I practice on the clear side. Practice techniques, mixing paint colors, shading, etc. When finished just wash it off and you have a clean slate to work/practice with again