A trading journal records...

Reason, stop, target, result and feelings

Most improvement comes from...

Fixing your biggest repeated mistake

They show the mistakes you can fix

Athletes watch replays of their games. Traders can do the same with a trading journal. It turns every trade, win or loss, into a lesson.
For each trade, write down: what you traded, why you entered, your stop, your target, your size and the result.
Write how you felt too: bored, scared, greedy, out for revenge. Emotions leave fingerprints on your results.
After 20 or more trades, look for patterns. Which setups work? Which times of day? Do you break your rules after a loss?
Example: a trader reviews 30 trades and finds that 8 of her 10 biggest losses came right after another loss. One new rule, stop for the day after two losses, fixes her biggest leak.
Common mistake
Mistake: only recording the wins. Losses hold the most useful information. A journal you can't be honest in is just a scrapbook.
Key takeaway
Record every trade, review every week, and fix one mistake at a time.

A trading journal records... Reason, stop, target, result and feelingsThe why and the how you felt matter as much as the result.
When should you look for patterns? After a number of tradesOne trade is luck; patterns appear across many trades.
Most improvement comes from... Fixing your biggest repeated mistakeOne repeated mistake can cost more than any new strategy can earn.
Why record losing trades in detail? They show the mistakes you can fixLosses are where your most useful lessons hide.