Set up a well-ventilated painting area. Fix your canvas to a board or easel.
Assemble the unit. Slide the needle into the front shell of the airbrush. Fix the needle to the unit with the needle lock nut. Screw the back shell to the base and handle of the brush. Attach the tip of the airbrush, one piece at a time. Follow the instruction manual if necessary.
Connect the hose to the airbrush.
Mix the acrylic paint with water until it reaches a milk-like consistency.
Fill the paint cap with the mixed paint. Tighten the cap lid. Make sure the compressor pressure is very low (5 to 10 pounds per square inch, or PSI). Slowly increase the air pressure to around 20 PSI or until you find a pressure that works best for you.
Press the trigger to release a stream of air. Pull back on the depressed trigger to release a stream of paint. Practice using different combinations of these two actions to achieve varying line widths, shades and spray volumes.
Play around with the distance between the paper and the airbrush. Find a distance that best suits the artwork. If the airbrush is too close, it will cause splatter on the artwork. If the airbrush is too far, the line will appear faded.
Maintain a smooth and steady spray when working. Keep your arm moving in a continuous back-and-forth manner. Keep your wrist locked into place and spray with your arm and body for more consistent results. Always keep your hand parallel to the working area.
Allow 4 to 6 inches of overspray so you can stop the flow of paint, by releasing the trigger, at the end of each stroke. Do not stop the paint flow on the artwork -- it will create blobs of paint on the piece.