Good luck. I am doing the same as you, I recently bought a good pair of clippers and I am going to start grooming myself. I have a cocker, which I groomed when I got my clippers, I cut her pretty short that time but I usually do that in the summer any way. She is about 4 weeks on her grooming and it is time to shape her up a little. I also have a shih tzu that I will be grooming next week. I look at it this way, if I do a bad job no one is going to see them but us and it is hair and will grow back. I will just keep trying until I get exactly what I want. When I groom my shih tzu I am just going to go slow and easy and if it takes me all day to do it and do a good job, then so be it. I am going to try my best. I have 5 dogs so this is going to save me a ton of money on grooming, my other 3 don't need to be cut a whole lot so they are going to be no problem at all.
I just ordered my first pair of Clippers
This is what I ordered off of Amazon: Andis 21420 Pro-Animal 7 Piece Clipper Set, Purple" I hope they're decent. Better yet, I hope I can groom Dallas. I was going to order a "Pet Grooming for Dummies" book but figured I'd save the SH and just go to the store and find one, or Ebay. As you all know, I've never groopmed a dog before, and I'm not all that clever, so I can't imagine what poor Dallas will look like when I'm through, wish her luck. But, if I can do this, I'll save $$ and she'll be groomed more often. 
If not, I just wasted $$
If not, I just wasted $$ 
