QFT. I was contemplating writing up a comprehensive guide for my guildies until I saw DD's write-up a few months ago. It's a wheel. I might put spokes on the inside or rubber on the outside, but the wheel part, I'm not re-inventing that.
In particular you'll want to read and re-read what DiscoDoggy has to say about synergy. It covers a fairly decent percentage of his multi-post guide because, once you figure out the Human v. Undead=dead Human part, and the P/P, S/S, and all lesser breeds part, it's all about the varying forms of synergy.
And, Grothia, if you want more people to throw in some advice, pick your favorite pet. A team can be built around your favorite pet, maybe as a poor substitute for a better pet in that role, but it will certainly narrow things down for anyone wanting to help.
Now, TeaCake, stop spamming Disco's link. Seriously, I'm ~190 wins from Trainer. I don't need stiff competition down the final stretch, so knock it off