I made a post in the healer thread for SCH DPS spell selection. I think this is important for SMN to know as well. Obviously, all your DoTs should be up all the time, but there are situations such as when there is high movement or you need to re-start the rotation (when you first start, or after some long mechanic)

Quote Originally Posted by YuriRamona View Post
Total potency
  • Bio II: 0 initial potency + 350 potency over 30 seconds = 350
  • Miasma: 20 initial potency + 280 potency over 24 seconds = 300
  • Bio: 0 initial potency + 240 potency over 18 seconds = 240
  • Thunder: 30 initial potency + 210 potency over 18 seconds = 240
  • Shadow Flare: (0 initial potency + 250 potency over 30 seconds) / (3.0/2.5 corrective for cast time) = 208
  • Aero: 50 initial potency + 150 potency over 18 seconds = 200
  • Miasma II: 20 initial potency + 50 potency over 15 seconds = 70
  • Energy Drain: 150
  • Ruin II/Ruin: 80
DoT's damage per second
  • Bio: 240 / (18 sec duration + 2.5 sec cooldown) = 11.7
  • Thunder: 240 / 20.5 = 11.7
  • Miasma: 300 / 26.5 = 11.3
  • Bio II: 350 / 32.5 = 9.9
  • Aero: 200/20.5 = 9.8
  • Shadow Flare: 300 / 30.5 = 7.5
  • Miasma II: 70 / 17.5 = 4
Considerations:
  • Bio, Aero, Miasma II, and Ruin II have instant cast times on the global cooldown.
  • Miasma II is AoE across 5y, so it beats Ruin spam at 2 targets and is a viable DoT at 3 targets.
  • Shadow Flare can inflict a Slow effect, and will replace Sacred Soil if it is in effect.
  • Bane will generally yield higher damage for your aetherflow charge than Energy Drain as long as Bio/Miasma/Bio II have more than 6 seconds remaining.
When you don't have global cooldowns to spare, use the total potency chart to pick your spell.

When you can afford to apply DoTs back-to-back and time is an issue, use the damage per second chart.
Obviously Thunder is no longer relevant. Sorry to bring up that painful memory. And Aero is not usable by SMN.