Change comes through repetitive small actions. Make a game out of improving your focus and concentration by giving yourself specific goals to meet and then slowly increase your goals. For example; I'm going to observe the next 3
hands without being distracted. I'll test myself at the conclusion of each hand by recalling the action by position of each player. eg Button raised, the small blind 3bet, BT called. The SB Cbet and then check-called the turn and folded river. No showdown.
If you can do that for 3 hands in a row, whether you're involved in the hand or not, you will have developed your observational and concentration skills, and you'll be alert and focused. Then shoot for 5 hands, etc.
You must manage your mind or it will manage you.
As far as advice on how to keep track, you need to pick the main factors to focus on and keep them in the same order so you develop a pattern.
-Players position and their line of action
-Board
-Bet sizes
-Specific cards / hands shown down
It takes great skill to do what you're doing - while you're doing it!