My priority rotation has been this:
1. Keep living bomb on target at all times
2. Spam scorch until I hit a Hot Streak
3. Hit an instant Pyroblast
4. Hit an instant Impact when they are near a group or need to be stunned
5. Hit combustion when I have a living bomb + Pyroblast crit on them
6. Blast wave disorient + flamestrike + Dragon's breath + Nova + blink to mess with mobs
7. Dragon's breath if someone closes on me and blink/CoC/Nova are down.
8. Blast wave if everything else is down.
Any advice, suggestions, ect. are welcomed. I just started playing fire like 4 days ago, so most of this is of my own design. My thanks go out to the Mage's forums in helping me thus far in gemming, enchant, glyph priorities.