I just shaved mine down for the summer and used a 1/16th comb on a #40 blade. I was using a 1 1/4" comb over the winter with their long coats. I use scissors on the faces, legs and butt area.
I also followed the groomers lines on Hot Rod at first and then just started experimenting a little. sometimes it didn't quite work out like I wanted, but the good thing is that the hair does grow back.
I got the dvd that was mentioned above and must have watched it 20x before getting up the courage to do it. lol It's been over a year that I've grooming my , so there is hope! Good luck!