Hawk Sugano has devised a system he calls Pile of Index Cards (PoIC). It’s a combination of a "brain dump" (emptying one's mind of all important information by writing it down), long-term storage for reference, and David Allen’s GTD method.
This is a one-liner journal. There is one index card for each day of the year. You write the date: then a sentence about what you did that day. Cycle through, and you should be able to do this for 14 years because there are 14 lines on the index cards!