I used to work for a puppet theatre, and we did a lot of paper mache. The education director decided to try her hand at making a pinata for her son's birthday, and using this recipe, doing three coats, actually had to saw the thing open like Steve Martin on Parenthood.

1. Golden Harvest Wheat Paste (I find it at True Value hardware store. It's not expensive and it goes a long way)
2. A Bowl with Water as Warm as you can get it (Hot is good, too)
3. A Fork or a Whisk
4. Ripped Strips of Paper (It's very important that all the edges are ripped and not cut. Scissors snip the fibers of the paper all the same length. Ripping feathers the fibers, giving the glue way more surface area to work on with the edges. Strips of cut paper unravel. Ripped paper holds fast.)
5. Something to paper mache around (we carve things out of foam, especially hard pink insulation foam-not the fiberglass soft stuff- from Home Depot. It keeps a nice smooth edge as you're carving. Styrofoam's a little bumpier.)

Step One: Stir water with with fork, and gently "salt" the water with the wheat paste. It's important to keep stirring. You want it evenly dissolved. Lumps, or as I call them when I do this with kids-boogers, weaken the paper mache (when it dries, it's like your mache has little gravel in it, and it rips easily). Keep "salting" until the liquid turns the consistency of: honey, applesauce, cream of rice cereal, snot (you get the picture).
Step Two: Take your ripped strip of paper, dip it completely in the glue, take it out, crumple it up (you want to break the fibers up in the paper, it helps it adhere. I picture it like I'm making a solution of fiber and glue). Scrape all the excess glue off the strip (extra glue weakens it, just like lumps). I do this by pulling it through two closed fingers like clothes through a ringer.
Step Three: Lay the strip flat against what you are paper macheing (balloon, toilet paper tube, foam, whatever). Make sure it's flat. Bumps weaken the mache.
Step Four: Repeat. Make sure that as you apply the strips to your project, they are going in different directions. If they're all going the same direction, it unravels like a mummy. I always give kids the metaphor: If you lay strips of string side by side, they unravel. If you weave them, then you have a net, and it's strong.
Step Five: Don't let this dry before you finish a layer, but you can let it dry between layers, although you don't have to. Your project, will be smooth, paintable, and indestructible. (Unless you're a touring puppet company, in which case, you'll find a way to break it!)

Hope that helps!
Cheers,
Katy