I’ve been using this tutorial written for me by an old friend by the name of Tiari for about five years now. I no longer need this tutorial; I’m so familiar with the process now that I’ve memorized it but I get frequent questions asking me how I make my family trees so I’ve decided to post Tiari’s image tutorial here for the benefit of others since Tiari has been inactive for several years now (to the best of my knowledge) and her blog can no longer be found.
The guide is suitable for beginners and contains screenshots and examples for every step. The tutorial was made with Photoshop 7, but I had CS4 while I was learning from this tutorial and was able to follow it with relative ease, so you should be able to follow this tutorial with any version of Photoshop.
(Click the images to enlarge them and view at full resolution)