
Whatever floats your boat I guess.
Somehow you need to entice the adult element. Kids are great, but I'm not sure that, if I was an arcade owner, I would enjoy seeing the classic get beat up. Of course, I'm the kind of person that gets really irritated when friends, pizza, and the game console are all in the same room.
Anyhow... looking at a the few successful running arcades I know of.
Forgo coinage entirely. Kids don't seem to get dropping coins through the slot. Teaching the seven year old that four quarters == one dollar is not an easy task. One place here has refillable "credit" cards. A small fee for the card itself plus whatever to fill it up. The kids, especially the young ones, caught on to using the card, fast. They caught on so quick, that most of them figured out how to check card balances on any cabinet. They also burned through the credits faster than I ever did at their age. The system could also allow all day passes ($50 gets you unlimited play for example), discounted memberships (pay for a years worth of membership and get 6 credits for every $1 on the card), etc.
Offer the adults something other than arcades. I believe that despite the fact that the early gamers are now adults, we're very far from the point of every adult playing games. Sell Beer/Wine? Offer daycare? Offer package deals where mom/dad buy junior a game card and mom/dad get a freebie from some store you've partnered with? The Daycare option might work well, but I'm not sure of the logistics of mixing people who are in the daycare and those who aren't.
Consoles. I hate to say it, but consoles seem to be a real cash cow. Tournaments, etc, seem to be how a lot of game related businesses stay afloat. One thing that always irritated me about consoles is how every place seems to have them set up. Long folding tables with TV's, and folding chairs. WTF? That's so 90's. Consoles beg to be played best from a nice squishy couch, beanbag chair, or thick carpet. Toss around some beanbags, enclose your consoles in an acrylic box with a nice TV on top (or on the wall) and security measures for the controllers to prevent theft (deposit for instance). Charge flat rates per hour, game or whatever.
In this day and age, I have a hard time finding a local arcade that doesn't offer food. eg All-you-can-eat pizza.