There's really nothing that you can do. MS warrior/enh shammy is a bad 2's combo. Especially if you have bad gear. It wouldn't be that horrible if the shaman was resto, but seeing as how he's not, I'm not surprised that you went 1-12.
If you insist on keeping this combo, then try to get on the squishiest thing possible. Well, except maybe a mage (I can never catch them ><). Nuke nuke nuke. If you can down one person and still have both of you up, you'll probably win. Make sure that if your shaman isn't being nuked, that he's throwing out heals. He may not be able to get many off (low mana for enh) but anything will help. Most combo's in the (I'm guessing you're down into the 1300's now) will be really bad healer/dps teams, or double dps. Basically, if you can outheal, you'll win.
That's about all I can tell you. Well, other than have the shaman go resto.