Lightning Bolt is a staple damage spell for an elemental shaman. The recent change to Elemental Focus made elemental shamans problem with running out of mana quickly significantly more manageable. Now all of our crits will give us a free cast of our next spell. This means that we should focus on crit as a stat significantly more than we used to (in fact, spell crit is probably more important than mp5 or int now). Anyway, the upshot of all this is threefold:
1) If you have time (depends on range to target), try to use max-rank Chain Lightning as your "free" dps spell.
2) When you go out of mana, don't just stand there! Cast rank 1 Lightning Bolt (0.5s cast time) And when it procs a free spell, cast your biggest damage spell. With 25% crit rate, we get to cast a big damage spell for free every couple of seconds on average. (and this big spell can also crit

3) In addition to the above, note that we have a quest reward green totem that reduces the mana cost to cast lightning bolt by 15. The cost of Rank 1 Lightning Bolt is... 15! This means that the spell that we plan on spamming every 0.5s is free to cast and the big spell that we cast on a crit is ALSO free to cast. The reason this is so relevant is that FREE SPELLS DO NOT TRIGGER THE 5-SECOND RULE. This means when doing the "cast rank 1 LB until crit, then cast biggest spell", we are regenerating our mana as if we are out of combat! (Note: if you have Elemental Mastery, the same thing applies here.) Finally, paladins have (EDIT!) Seal of Wisdom (judgement) that helps us regenerate mana every time we do damage to a target. Rank 1 LB works fine for proccing this bonus! (This is an extra 74 mana every .5 of a second, while outside the 5 second rule!)