I have no fast way. But I can share what I did.
I keep a spreadsheet.
Each row is one trade. Columns include entry price, exit price, dates, stops if any, reasons for entry/choice, outcome evaluation.
This is fine for slow trades. E.g. if it's based on hourly or daily charts.
For fast trades, like 1 min or ticks, I also use a video capture software to record my thoughts. Specifically, I use Snagit.
I'll start the recording when I think a possible entry is forming. I'll verbally speak into the mic to record which set up is forming.
If the entry does occur, I'll continue recording. If the entry gets invalidated, I'll pause the recording.
Similarly, when an exit is coming up, I'll unpause the recording and verbalize my thoughts.
At the end of the trading session, I'll playback the whole capture and take my time writing down the journal.
Such a video log is almost 100% capture of my thought process and mouse action. You'll be surprised at watching your own mouse action when greed and fear rushes in.