basically what you said is what you should do. Locks are very powerful, even when not twinked, at 29 you will do a whole lot of damage and with the fear dot drain life tactic, you should survive almsot every one on one battle you have, even against twinks. (hunters will most likely mow you down if they know what they are doing)
TLDR:
Fear , dot, dot ,dot drain life works very well, even when you arent twinked out.
Good luck,
PIE.