In all seriousness, I wouldn’t do it.

I’d take the dog to a professional dog groomer, and let him/her be “the bad guy,” because dogs really don’t enjoy that.

Believe me, the fees will be worth it, and your dog will look terrific!

I had a Lhasa, which is a lot like a shi tzu. Definitely let the groomer do it. We always had Fluffy cut down… she was so much more comfortable. And more adorable! We wanted a dog, not a mop :)

One word: Groomer.

I had a friend who had a Lhasa Apso, and bought his at a kennel where they had LOTSA Apsos. (Go ahead and groan.)

Anyway, what they did with her one day, was they sprayed a little bit of ENDUST® on her underside, then place her on top of the mahogany dining room table.

As she walked around, the table got polished.

My Lhasa was always buzzed short, not fuzzy but a little furry, with long hair on the tail and ears.

http://www.amazon.com/Grooming-Your-Dog-BASIC-HAIRCUTS/dp/B001AQM48O/ref=sr_1_3?ie=UTF8&s=dvd&qid=1221012926&sr=1–3
If you really want to learn how to do the clipping yourself, you may find a video helpful. But first, take the dog to a groomer who will let you stay and watch the grooming. Look carefully at the equipment they use and how the professionals go about the whole process. Then, with a good video to watch, you can start learning to do it yourself. Your first attempt may not be perfect, but you surely can learn how to do it if you are determined.

Hire a groomer and tell them to use a # 5 blade.

I bought clippers and use #8 blade. There was a DVD which showed you how to clip them. Then I use a slicker brush to finish them off.
It takes time and lots of patience, but they look really lovely when finished.