You need to know your job and its capabilities. I have ran with undergeared people who did not have their correct rotation down. We couldn't kill the first boss' adds before another add came out.

Then again, I have ran with other undergeared people, who knew their rotations and could complete the entire instance.

Buy cheap level 50 accessories, a cheap level 50 weapon, and, you should be set! After your first AK, buy your GC weapon.