Practice, using scrap materials, other applications such as thin lines and shading from one color to another. Avoid spraying at an angle or with excessive force along tape-masked border to keep paint from leaking under tape edge. Clean your airbrush tip by spraying water, with a bit of liquid dishwashing soap added, through it after painting with acrylic paints. Use common rubbing alcohol to finish the job as necessary. Like any creative skill, painting with an airbrush comes easily to those who practice most.
Hobbyists can find premixed paint in authentic colors.
Wear a paint mask when using an airbrush. Safety goggles are useful as well. Always use an airbrush in a well-ventilated area or in an open area. Paint particles can overspray and damage other objects. Inc. How things get done.