Why keep a journal
Memory is selective: we remember our best trades and forget repeated mistakes. A journal turns impressions into numbers and shows you where you really make and lose money.
The traders who improve aren't the ones with the most complicated strategy, but the ones who measure every trade and fix one thing at a time.
What to record for each trade
The essentials: instrument, direction, entry, stop, target, exit, size and result in R. Then the context: the setup, your mood before entering, whether you followed the rules and which mistakes you made.
A before-and-after chart screenshot is worth a hundred words: looking back at it, you'll understand whether the setup was really the right one.
When to fill it in
Right after closing, while the details are fresh. An app that imports trades from the exchange leaves you just the notes to complete: 30 seconds is enough.
At the end of the week spend ten minutes reviewing: what worked, what didn't, which single thing you'll change the following week.
How to read the data
Look at expectancy in R by setup, time of day and mood. If a setup has negative expectancy after 30 trades, stop trading it. If you perform worse when tired, don't trade at those times.
Compare trades where you followed the rules with those where you broke them: the difference is usually huge, and it's proof the method works when you follow it.