Never forget that a contract is meant to be negotiated - a contract's first draft typically contains a bunch of unreasonable or vague requests and wishes from the party that created the contract. Don't sign a contract until the vagueness has been clarified or defined.

It's up to you to negotiate the contract in your favor. To put it plain and simple; unless you negotiate a contract in your favor, you're going to have a bad time. Like the video said; if you have no contract, you're left with the sympathy card and that rarely works.

Another bit of advice: Keep track of all communications and have all word-of-mouth agreements put on paper (before you commit to anything, like signing the contract). I keep a projects folder per client containing communications, documents received etc.

Hourly billing only works when you keep a detailed log of what was done. It's definitely a lot easier to get paid for work if you provide a breakdown on what was decided and done. The descriptions should prove as motivations of why the work was necessary.