DNC's playstyle varies a lot between different situations. We have some tools that are difficulty to use in a party setting (like self-skillchains) or have penalties (like JA Delay) that are difficult to ***. In no particular order ...
Steps:
I have three step modes:
1) Don't Step at all - Old content with high Haste.
2) Only Step when I can combine it with another ability usage - Current endgame trash monsters
3) Try to maintain Sluggish or Lethargic Daze Lv.5 - Current endgame boss monsters
You always want to try to combine a Step with another ability use, but against some current endgame bosses I feel it is worth sacrificing a little more damage to maintain the buff for the party. I use Presto between monsters in mode #2 and I use it when it's up in mode #3. I never find myself wanting to use Feather Step or the forgotten stepchild (Stutter Step), but I can't really back that preference up with anything.
No Foot Rise:
This is useful for giving quick TP. You could use it when you miss a step, but I typically use it and Reverse (or vice versa) between monsters.
Reverse Flourish:
Reverse Flourish allows us to make self-skillchains, which is the most efficient use of our Finishing Moves bar none. However, in party settings with Marches it is difficult (not impossible) to pull off self-skillchains. That does not mean that you need to stop skillchaining. You just need to watch your allies' TP, know the skillchain chart, and skillchain off them. Now, you don't want to waste finishing moves, so if you are about to re-engage/Presto+Step and have FMs from the previous monster, you should reverse flourish between monsters.
Wild Flourish:
Self-skillchains against old content are often overkill. In such situations, it is better to use Wild Flourish -> WS and spend fewer FMs for a smaller WS damage boost (+60%) that overkills less. This is our second most efficient way to convert FMs into damage. Unfortunately it relies on skillchain mechanics again. Remember to wait a second or two after Wild Flourish before WSing or it won't skillchain. I like to do:
Presto (before engaging) -> Wild Flourish -> Box Step -> WS
because it enforces that delay and restores my FMs (and often burns extra TP that I had from the previous monster). Be aware that Wild Flourish will not take effect if the monster has recently been WSed and the skillchain window for that WS is still open. It also only works with level 1 skillchain properties.
Sambas:
There's pretty much only Haste Samba. Unless you're killing one or two EEP monsters and warping (or using Fan Dance), you should have it up.
Saber Dance:
If you are fighting old content monsters (capped evade rate, low damage/hit, etc.) then you should probably be using this ability full-time. Unless you currently need to Waltz or need Fan Dance's durability, this ability could be up.
Fan Dance:
Fan Dance is for moments where you're willing to sacrifice Haste Samba in exchange for physical durability. In the past, people hit this ability after being dropped by a big unexpected TP move. Now, fulltiming it is useful against the more one-shotty current endgame (like AAs).
Waltz:
Use it if you or your party is dying. If you have a WHM in your party, there should be no need to Waltz most of the time.
Misc:
Climactic Flourish - Useful with Rudra's Storm. Probably our best option from Flourishes III
Building Flourish - Sort of a second-tier buff like Wild Flourish. It'll increase your damage (sometimes), but not as much as the 1/2 a WS that it costs you.
Animated Flourish - It's Provoke with 2 FMs. Seems like a waste to me most of the time.
Striking/Ternary Flourish - These increase damage, but are a less efficient expenditure than Reverse or Wild Flourish.
Violent Flourish - Use it to stun. Its maximum stun rate is 95%, so don't strategically rely on it if you are dealing with bad TP moves.