Title says most of it, I've got a tournament coming up in a week's time and I'd really appreciate some tips about how to go about things, I'll list the models I have available to me at this moment (I might be able to get a few more things if you think I really need them, but other than that this is all I have to work with):

Archaon (Can be used as a Chaos Lord)

Chaos Lord on Daemonic Mount

Exalted Hero
Exalted Hero
Sorcerer of Nurgle/Hero of Nurgle (flyhead)
Tzeentch Sorcerer

36 chaos warriors

6 Warhounds

10 Chaos Knights

10 Marauder Horsemen


6 Trolls

My main opponent (ie, the one I'd really like to beat) brings a list with 50 bloodletters, 6 bloodcrushers with Skulltaker and a Herald of Khorne in it, 5-10 flesh hounds and a Keeper of Secrets.

So basically, A. How do I use my models to their greatest effect
and B. What can I do against a list like that?

All comments and hints welcome! I don't want him to beat me again.