Go to Disboards.com - they have all sorts of tips there

I'll second the water bottles - they get $3 for water at the park. To extend this tip, get the Brita sports bottles that have the filter built in. They have water fountains in the park (Not many, but they are on the map they give you) but the water down there is pretty bad. With the filters, it's MUCH better

Disclaimer: I work for a company that is owned by Disney Corp, but have NOTHING to do with the parks, except having gone as a "guest"