Greythan

A good boss fight to try to learn controlled DPS is the Vexallus fight in Heroic Magister's Terrace. In that particular fight, if you DPS too quickly without killing adds, you'll end up wiping as the adds have a pretty mean AE.

On normal mode, you can DPS so quickly that it doesn't matter, but on Heroic, you either need huge DPS or you need to control the encounter. Anyways, it's a fun fight and may help you get a little more comfortable with controlling DPS.

I'm not one to really talk, though, as I get spastic on Heroic Boss fights as well!