I wrote a little about it here: http://www.digitaldjtips.com/2011/05/how-to-succeed-at-djing-marketing/
I just finished reading a book on designing logos. What I found is you should think of your name and what words, thoughts, images, etc…come to mind. Jot down or sketch those words and visions. What’s your musical style? That will also dictate the look/feel you’re shooting for.
From there, either design it yourself or seek a designer and give him/her your input and findings.
My logo looks very simple, but I wanted it that way. I wanted it unassuming so I could play any genre I like and not be typecasted by my logo.