How effective is coaching?

[Andykay]

Obviously that question in the title is somewhat subjective, but i'm just curious of some of the basic things people have gotten out of coaching arrangements. I play NL200 at the moment on a $4,000 roll. I used to play NL400 on a much larger roll, but a bad downswing+break+cashout large quantities of cash has left me starting again.

I'm doing basically everything I can to break back to mid-stakes and stay put there. Card runners, as many books as I possibly can, camping every post on 2+2, so i'm wondering if a coaching arrangement is the next logical step. I particularly want to work on increasing my aggression. I currently play about 23/16/1.8 but would like to work on increasing the aggression factor post flop and 3-betting more preflop. Although that's just one area I know needs improvement.

Any help would be appreciated.

-Andy