Did anyone mention pictures yet?
As everyone is saying, pictures from every angle for every step. Yes, you may end up with hundreds of stupid pictures... And that one snapshot that tells you how it goes back together.
Also, do NOT assume the last person that worked on the game put it back together correctly. That hex post that is 1/4 inch shorter may not have been in the right spot when you took it out. Sometimes that just makes things look funny, and other times ball flow may be impacted.