One word, practice. You are going to have to buy at least 4 more fjords to get really good at it ; )

I like the page that Zhuria posted. It is pretty much exactly how I tell people to do it. I have posted before somewhere on here about how to do it, but it pretty much just repeats everything posted above.

It is also possible to do it with a clippers, but if Constantine moves around a lot I would stick to the scissors. You should have seen the first mane I trimmed. It was a disaster. I've gotten better with 5 to practice on, though. It takes time, and don't worry about screwing it up...because you can just roach it off and start over a few weeks later!