Trading journals should include all necessary elements that describe a trade, like the date and time of the trade, the traded instrument, the direction of the trade, entry and exit prices, position sizes and therefore the results of the trade once it's closed.

Besides these main elements, a well-designed trading journal should include additional information also.

Those additional entries will assist you keep track of your trading improvements and make it easier to analyze your performance

Trading journals can be very helpful for a trader. For each trade made the trader can record key details about it in this journal, and this data can then be used as a form of reference as well as to enlighten the trader on ways to perform better decisions in the future. This is because you can easily see what you did, and how you performed, if all trades are recorded in the journal.