Keep a log book:

[AndyS]

Don't rely on your memory.
Write it down!


Keep a detailed record of when, where, and how fish are biting.
Observe and follow patterns in a particular target species.
Build a knowledge base that can help you predict when and where fish will be biting.
Identify successful fishing methods.
Track and record catch history.


Body of Water, Weather, Water Conditions, Fish Species, Techniques, Date of Catch, Pictures

There are many types you can purchase.

I've printed out some reports from here and saved them, printed out some PM's and saved them. I also keep receipts and hotel information in my log book.