COR is pretty much what you make it...
/rng or /war to DD, either shooting for tp or meleeing (both works just fine, just dont mainhand mkris, joyeuse give you a way better DoT)
/whm to backupheal
/dnc to do both
/blm or /rdm for Quickdraw
/nin to pull and when you need not to take dmg (aoe stuff ect)
/sam is kinda fun when just shooting for tp, and seigan helps alittle when it comes to not taking dmg, but i find /war and /rng better for dding anyways.
And this is a very expensive job, if you dont have gil, dont level it.
Short and simple!
When it comes to stats, you dress it like a ranger when shooting, just add some more racc, and when meleeing, haste and acc as on all other jobs that melee, but you might need more acc on Cor.
When /whm some dress up in full mp-gear (I do, and I find that 500mp helps quite a bit when it´s needed), but other dont give a damn and just use the mp they get from the sub.
When you pull just dont use "decreases movement speed" gear:p movement+ helps alot.
Merit QD on group1 and whatever you prefer on group2.
Edit: Forgot QD gear. Just spam MAB where you can, add MACC and AGI everywhere else. Ele-staves help a ton too.