Write before the trade, not only after. Three lines are enough: setup, entry level, the level where the idea is wrong, and risk in dollars. If you did not have time to write it, you did not have time to take the trade.
Afterward add the fill, the exit, and whether you followed the lines. A win that broke the plan is not a good trade. A loss that followed the plan is not a failure. Grade the process, not the color of the account.
Once a week, not every night when you are tired, you count. How many trades followed the plan. Average win versus average loss. Which setup made the mess. A setup you cannot follow should be paused, not tweaked every day.
Read the journal out loud to someone you trust. Hearing your own excuses is unpleasant, which is why it is worth it. Grade the process, not the next order.
Save a screenshot of the trade itself, not of the account balance. The balance mixes luck, size, and skill. The picture of the level shows whether you saw what you said you saw.