Ease of use:
Keep painted areas clean.
Choose a clean, suitable brush.
Apply paint with a brush or sponge (no water needed), use a single color or mix different colors to achieve your desired color.
Use a large brush or sponge to give you excellent coverage and glow; fine lines and details with a fine brush, or directly with your fingers.
Use a stencil if you're not confident in freehand drawing or if you're pressed for time.