Find simple geometric designs that are of interest to you. Designs are everywhere, from borders on book covers to doodles on old notebooks, design books created expressly for permanent and non-permanent tattoos, such as henna tattoos, and the Internet. The trick is to find designs with varying levels of complexity and with easily discernible repetitive shapes.
Select the easiest design among the designs you found. Choose one that is bold and consists of simple shapes. Trying to draw a photograph or image is not necessarily a good starting point.
Place tracing paper over the design, and trace the design. An alternative is simply to look at the design and draw it freehand. Everyone has her own style, but drawing a rough outline first is useful in learning the design. Use the fundamentals of geometry: Locate the simple shapes, lines and angles in order to get a feel for the design's symmetry.
Practice drawing, and gradually choose more complex designs to draw. Draw the same designs that you like over and over until you can start drawing straight on skin without the help of tracing paper.