First off, get your gear up at this point there's really no excuse to be 250-260, from there meld for you stats (as a dps main I cannot advise on tank melds but I will suggest look at top tanks and see how their gear meld is set) from there run mechanic heavy ex primals, thordan, sephirot, etc once your comfortable with mechanic recognition go to SSS and fight those dummies as it were the only thing to do in the game, once you can kill the 9s and 10s dummies within a reasonable time (i.e. with spare time left on the clock) then I would attempt the actual floor starting with 9s. It seems like a long process before actually getting to content, but the fact is as this content ages more people are looking to perfect the fights instead of learning them especially 9 and 10 as many consider these floors almost faceroll.