Great poolrooms begin with solid business plans. I know that's the least sexy answer one can give but a closed room always sucks. In my opinion, you need a management team that is flexible and professional. You want people that know the game well, that know the bar industry well, and know event coordination.
You want your room to be everything. It should be great for leagues, tournaments, events, and still be the best local pub in town. To get there, you want to have full control of your environment. No public jukebox but definitely a solid sound system with full access to any kind of music genre. You want a bar and wait staff big enough and professional enough that nobody has to wait for a drink but also mindful enough to know not to bother the serious players. You'll also need people dedicated to cleaning because bathrooms. When that group of new customers goes to the bathroom, let them be pleasantly surprised and not disappointed or grossed-out.
Then there is furniture and equipment. Obviously, you want great tables that are regularly maintained but you'll also want comfortable seating throughout the room. Ideally, you'll want cocktail-height chairs near your pool tables and conversational seating elsewhere. I love Amsterdam Billiards' arena style head tables. I think it's great to put the game on display and give your waitlist something to watch.
Rates can AND SHOULD BE flexible. You don't have to charge your regulars the same price as your walks-ins. Create a structure that encourages your serious players to play during off-peak hours but always remember, your rules are meant to be broken.
I'm not a big fan of food, mostly because food complicates things. If your room serves frozen food, people will say it tastes bad. If you serve fresh food, you'll struggle to break even on cost. That's not to mention the health inspection you have to pass. If you can swing it, the best bet is to partner with local restaurants, encourage food trucks to park in your lot. There are lots of options there. Either way, your customers shouldn't be hungry and you should take an active interest in finding a solution. It would just be ideal if that solution wasn't your responsibility.
I know a lot of people point to Steinway Billiards as a great food location. I think Steinway has a lot going for them. They serve mostly diner food in an area that has no diners and they have a lot of backgammon players using their diner area. They're also an old poolroom and established themselves as a diner/backgammon venue long before serious pool players *really* started going there. I also believe the owner actually owns the building and probably bought it before Astoria real estate boomed.