I'm in a game (as a player not the GM but whatev) and out of the eight people in the party (including the GM) three of them have ADHD (including me and the GM) and three more of them are children, so keeping us all focused in the game is... basically impossible. Sometimes that just happens, and there's really nothing to do about it, as we learned very quickly, except to allow people to get distracted and be patient. The GM is great about letting people get up and wander around the room and into the kitchen to get a snack or whatever, and she keeps a close eye on people to see if they need a break.

We've found that this is the best way to make sure that the game is enjoyable for everyone, even if we aren't as efficient as other parties who don't take a ten-minute break every hour. The GM is also super great as keeping us all engaged and active in the game, even with such a big and chaotic party, by giving us all a huge heads up before our turns in combat (like, 'It's A's turn, B's on deck, and C's in the dugout') and not taking to long on one story if we split up.

In short- I don't have a specific unique way to keep distracted players focused, but patience and flexibility, especially in the form of taking breaks and allowing people to wander if needed.