There are two ways I use my trading diary-
1.
For exiting positions- I am mostly a swing trader. So my positions generally can last upto couple of months. For such a long duration, It is almost impossible to remember the thesis I had when I entered the position. So everyday I go through it to see the rationale I had while entering and whether it still holds valid or not.
2.
For review of closed positions- Every quarter I compile the list of trades that I closed in that quarter. I go through it to see all the mistakes I made and what could have I done better.
For every trade I make, these are the parameters I fill in my trading diary-
Trade Status:
Active/ To be filled/ Closed/ Cancelled
Trade Type: Long/Short
Success Probability:
Reward-to-Risk Ratio:
Time Frame: Daily/ Weekly/ Monthly
Entry Price:
Target Price:
Stop Price:
Close Price:
WHY THIS TRADE:
ENTRY REASONING:
TARGET REASONING:
STOP REASONING:
FOLLOWUP: If I make any updates in my position (like selling partially, raising my stop, etc.)
I hope this helps