opening hands ?

Read what the authorities have to say; until then, a good guide to stealing blinds in late position is to open raise anything you would have played anyway and throw away anything you wuold have otherwise folded. This can be adjusted for the particular table because sometimes the blinds are too tight and someimes they will defend anything.

As far as being tight, you should list the last 20 times you folded preflop, excluding MP and EP hands that are absolute trash. These guys will pick up on any systematic problems you migh have.