I think you can do this in more than one way. I'm keeping track of my P/L and Risk(initial entry stop) for each trade in a day. Let's say I made the following trades, commissions included:
1) P/L=-100 , Entry Stop=120, R/R=-0.5
2) P/L=200, Entry Stop=80, R/R=2.5
3) P/L=-80, Entry...