One thing that may help is to take copious notes on everyone at the table.
hands they went to showdown with in various positions, bet sizing tendencies, how they tend to play in position vs out of position, etc. That will help you pay attention to the table action when you're not involved in the hand. Sometimes I fall into the boredom trap and find myself pushing the action when I really shouldn't and that helps me sometimes.
Another thing that may help is to try to put opponents on ranges when you're not in the hand. Start preflop and adjust those ranges according to player style, board texture, etc for each street. If the hand gets to showdown and you're way off, mark the hand and review it at a later date to see if you can be more accurate.
If you have a comfortable
bankroll and feel you can pay attention, adding one table at a time may also help. Be careful not to add so many that you go on autopilot and stop playing your A game. Maybe add one table for a few weeks and see how you feel. If you feel comfortable, and it's not impacting your game, maybe try adding another if your attention still wanders. Eventually you will find a sweet spot.
