Consider an image you want to modify or use your imagination to come up with your own idea. Tattoo drawings tend to have a strong outline and detailed, graphic look.
Sketch the image using pencil and paper. For example, if you are converting an animal into a tattoo image, start with a strong contour, or outline, of the animal and then draw distinguishing details inside the outline such as eyes, fur marks, etc
Choose whether you want color for your image. If you decide to use color, keep it simple: Most tattoo drawings use a smaller palate, or variety, of colors than an oil painting. Fill in your colors over the pencil lines with illustrator's markers so that they don't bleed.
Draw a strong outline and some of the inside details with a black drawing pen. This will give your image a graphic look.
Erase any pencil marks on your drawing. Take it to your tattoo artist to transfer to your body.