First find a design that you like, then draw that design on to the fabric that is going to be embroidered (make sure to use a washable pen or marker so that the design can be washed out when finished)
I used a simplified version of the above picture.
Step 1: Embroider Your Design
I used the Instructable linked below to reteach myself some of the embroidering stitches that was used on my shirt. Embroidering is a lengthy process, make sure you have the time.
Step 2: Enjoy
When finished show off your work with pride.