Practice operating your airbrush. Load the paint, hold it in your hand and pull the trigger slowly. Aim the airbrush at a piece of paper. Pull the trigger even further, moving the brush left and right across the paper until the paint comes out in even strokes. Spray in straight lines and then make single dots with the brush. Pull your hand out farther from the paper to make the lines and dots thicker, then bring your hand closer to the paper to make the lines and dots thinner.
Soak a cotton ball in rubbing alcohol. Clean the area of your skin where the airbrushed tattoo will go by rubbing the cotton ball over the skin. The alcohol will strip all oils from the skin and will allow the paint to attache to the skin better. Remove any makeup, clothing or jewelry that may interfere with the airbrushing.
Choose a stencil of the human figure. If you would rather do the design freehand, practice airbrushing the human figure on paper. Start with the head, drawing a round oval on the paper. Then draw the frame of the body, with wide shoulders that narrow into a chest and then narrow even more into the waist. Draw the arms and legs next, adding any details you desire. Complete the practice drawing by adding the facial features and any finishing touches such as clothing, accessories or color changes.
Create your human figure, whether with a stencil or freehand. Place the stencil over the part of the body or skin that you want airbrushed. If necessary, attach the stencil to the skin using tape. Load the airbrush with the desired color and begin moving your hand before you press the trigger. Then, continue to move your hand fluidly as you apply the paint. Let your hand finish the motion before releasing the trigger. Switch paints and repeat the process until the design is finished. If you are not using a stencil, simply create the figure you made while practicing on paper.
Remove the stencil and allow the design to dry. If you are not using a stencil, simply allow the design to dry without touching or smudging it. Then, dust the design with talcum powder. The powder will prevent your skin's oils from resurfacing too quickly and ruining the design of the human figure.