I want to create online forms similar to Wufoo, but with the ability for people to save their work and return to it -- and also for multiple forms to be linked together. I'm not technical, and I don't want to hire a programmer to create a system which I cannot change myself. Seems like there ought to be something that's one level up from Wufoo in sophistication, but not so technical that it would require specialized knowledge.
The best way is to rely on an easy-to-use online tool that walks you through the entire process. The site should take the guesswork out of the whole thing. I'd suggest using http://www.fieldboom.com/ to create advanced forms because it does all of those things. You can even try it out for free to see if it meets your needs. And if you ever decide to do a survey, it can help you with that too.