Make sure you're weaving abilities that aren't on your normal cooldown. For instance, this is how I start my fight:
Heavy Thrust > Phlebotomize > Impulse Drive > Disembowel > Chaos Thrust > True Thrust > Vorpal Thrust > Full Thrust
That's the cool down combo, but inbetween attacks, you can throw in some job abilities (where it's safe to do so). So, anywhere in between there, preferably when Heavy thrust is active, you can do something like this : Impulsive Drive > Power Surge > Disembowel > Jump > Chaos Thrust
That's essentially how "weaving" your abilities work. You use abilities that aren't on the cool down while the rest of your abilities are so that you're continuing your damage with minimal downtime.
And I see this mistake a lot....Power Surge is ONLY used for Jump and Spineshatter Dive. People tend to think it's a damage buff for all attacks, but it only affects those two jump abilities. It immediately wears off after you use a jump. Be aware however, that Power Surge does NOT affect Dragonfire Dive.
Which reminds me, I know plenty Dragoons that don't even know what their abilities do. So please, make sure to study what each ability does. Please. I had a guy in coils doing only True Thrust > Vorpal Thrust > Full Thrust because "None of the other abilities seemed useful" and he could "perform these abilities and get the combo from any direction on the mob." Please don't be that way. I almost had a hernia. You are not outputting your potential damage by doing something like that. Especially if you don't even know what the abilities do and you're just pressing buttons and watching what happens.
Be aware of your aoe abilities. Yes, Ring of Thorns combos off Heavy Thrust, but that doesn't mean you should use it. Keep to the combo above. Ring of Thorns and Doom Spike are useful during fights where you need to kill masses...like the Feather Plumes in Garuda Hard Mode. Also, I've found that Doom Spike appears to be more effective than Ring of Thorns in aoe damage. Remember that Doom Spike is a cone aoe, and Ring of Thorns is a circle aoe.
Also, keep in mind that Dragonfire Dive is affected by Blood for Blood and Internal Release. Useful.
And as always, be mindful of your stun abilities. When stunning isn't important, you can weave Leg Sweep and Spineshatter Dive into your cool downs. In fights where it is very important that only the off tank stuns (ie. Ifrit Hard Mode), be very aware of the abilities you are using and do NOT weave Leg Sweep and Spineshatter Dive.
Lastly, remember to use Elusive Jump. A lot of people try to say it's useless, but it will definitely save you if you're in too deep. You'll lose a huge amount of hate, so you help the tank get hate back, if they lost hate for whatever reason or died, and it's very good for escaping aoe's that are just took big and you know you can't get out of quick enough...Like Tail Drive from Anatoboga, the last boss of Amdapor Keep, or the "blue" aoe lines that take up a majority of the room in the fight with Ash, the mid boss of Haukke Manor Hard.
..And then there's Feint. People say this ability is useless. There's no combo off of it or anything really. so what I do is test and see if the mob you're attacking can be slowed. If it can, Then put Feint into your rotation right after Phlebotomize. If the mob resists slow, you can ignore Feint entirely.
P.S.
Gil is spelled wrong in your signature, Joven. >.>