Tracking your sessions accurately.
Simply what I do.
I have long term roll (pensions/ISAs/ house) and short term life/poker/gambling roll. I have too much money flying about between sites and real life stuff to try and separate that lot. I try and only ever put money into the long term roll, though can't say that always holds. I already spread the money over so many sites I have no desire to introduce more transfers/complications.
I usually update the poker stuff on a spreadsheet the day after a session, but sometimes do 2 or 3 before I catch up. Betting spreadsheet is once a week or sometimes longer, as I do less betting than poker. I track poker by type of game/site. If I am losing at something I like to know even if I am very slow to do anything about it.