Keeping hate off casters? (BLM & SMN)

[Garnatian]

Always use both.

Generally with a group I mark, then:

Pull, flash twice, lay my Harlone combo on 1, rotate what I need, and flash in between to hold the rest. Even wih ape this usually keeps all enmity on me, and anything slips a quick provoke or shield lob and ey're back on.

The important part is the initial dual flash, and to simply flash between combos. Don't overdo it, but keep it applied.

I feel if you're able to pull that off, the DPS is pretty low.

[Ehayte]

Have been doing this in my AK runs

Shield Lob T1
Mark T1
CoS when the mobs get near me
Flash
Spirits Within T1
Flash
Rampart
Fast Blade T1
Savage T1
Check Enmity levels, apply force as needed (including your first RoH, SW should have given you a decent lead over even Reliced single target dps'ers).

Until you get to Savage Blade, you are switching off between GCD and non-GCD abilities, so it gives you a "leaps and bounds" lead even with AE aggro in less than 4 GCDs. Then, as the rest have said, flash more for AE groups, Combo more for single target groups.