No fancy tools needed. These make your prints look 10x better.
Start with 200 grit, work up to 600. Wet sand for smoother finish. Takes 10 minutes.
Spray on primer, let dry, then paint. $10 at any hardware store. Looks professional.
Suspend print above acetone in a sealed container. 10 minutes = glass smooth.
Brush on epoxy resin. Waterproof, rock hard, glossy finish.
Flame polish with a lighter (PLA only, quick pass!). Or use a rotary tool with polishing compound.