One of the keys to Getting Things Done (whether you mean David Allen’s system or just “getting things done”) is to have a simple, fast, and reliable way of tracking important information.

In the course of any given day you will think of a business idea, hear an important phone number, collect tasks you need to do, and accumulate a dozen other bits and pieces of information that you can’t afford to lose.  Some people jot these things down on the backs of restaurant receipts or other scraps.  Some like to use a PDA.  My personal favorite method is an old-fashioned pocket notebook.