What am I building?
Austin Drupal Newbies Meetup
If you don't know where you're going, you'll never get there.
Can be as simple or complicated as you like.
Usually formal document that accompanies a contract.
Defines scope of work in greater detail.
Anything not in the requirements is "out of scope" and must be negotiated separately. This is how you avoid "scope creep."
Quick and dirty page layout tool. Defines where things go not what they should look like. Helps flesh out functionality.
Similar to wireframes except shows where things are and what they look like.
Just get something on paper!