Really all you can do is go to the test dummies and try to make your castsequences a little tighter. With elemental shamans there's not alot you need to do as you cant really change the spell's cooldowns. Since lightning bolt is the fall thru spell, all you can try to do is make it so that you cast Flame shock when it drops off, Lava burst when the CD is up, and chain lightning when it's off CD.
That's really all there is too it. That is the tried and true way anyways.