The opener has been discussed a lot. Assuming EB build:
1. Prepot and Elemental Blast at 2 seconds.
3. Lava Burst
4. Fire Elemental
5. Stormlash + Ascendance (which some people macro together, some don't. I don't recommend you macro together always).
6. Lava Burst spam.
Some Shaman insist that your FE should be before flameshock so it gets "triggered" to dps boss.
My thoughts are that you want your Flameshock out first, so that you might get lucky with Lava Surge proces (which I've gotten 2-3 sometimes before even my first ascendance).
Either way though, the difference is probably not very noticeable over the entire fight, really.