I've received a few questions on why I don't cast invisibility to break the gdrag's aggro once I get the tame attempt off. I use that approach with cu sidhes, but they are not spellcasters. I find that with the frequency of spellcasting from the greater dragon, more often than not, the invis spell I'm trying to cast is interrupted, and the couple seconds of standing still (even with max Faster Casting) is enough for the dragon to swipe a claw into me. That's 50-ish hp in damage plus the potential for a bleed attack.
I admit that I am a clumsy macro-masher, so this could just be a matter of ill-timed keystrokes on my part, but I gave up the invis approach for greater dragons (and rune beetles, coincidentally - though I use direct peace on them, so they usually remain quiet throughout the tame attempt).
These are just examples of how I happen to do things - most useful for people who've never tried it before and want to see one way of approaching it. Your mileage may vary - and there are definitely more ways of accomplishing the same task! I am definitely not saying that my approach is the only way or even the best way. It's just one way
(That said, I'd love to see video demos of other approaches that I'm not so good at, if anybody else would like to share! FYI, I'm using the free CamStudio screen recorder software, the same mic/headset I use for Vent, and the Windows Live Movie Maker software that came with Windows... nothing fancy required. The only trick is that video/audio files have a 2GB max, and the raw footage is pretty big - that's why I had to break the dragon video into multiple segments and assemble them in post production. The first recording I did exceeded 2GB and I lost the footage).