I traded professionally for 4 years and used a trading journal since day one. Back then, I used word and excel to log data such as:

1. trade activity
2. pnl performance
3. mistakes
4. goals
5. volume
6. fees
7. best performing stocks
8. best performing strategies
9. profit ratio
10. win rate
11. etc.

A journal is the most efffective mechanism to look under the hood of your trading system and find out what is wrong. Without it, you don’t know what to do to improve and why you are losing.

I believe so much in journaling that I ended up creating my own online trading journal system.