One thing I learned when I was showing dogs is that the "quick" (the sensitive part that bleeds) in their nails will "retreat" the shorter you keep your dogs nails. SO, if you are going to trim nails yourself, just take a little bit! And then trim them a week later, taking a little bit. Gradually, you'll get the nails shorter without cutting into the quick. Also, all groomers keep a styptic (sp?) pencil (men keep these around for razor slips) handy to stop any nail from bleeding right away.
However, sounding just like a real expert above, I'm still taking Higgins to the groomer to have his done!