From chicago - but.... For what I look for in a field:
1) Location - Not in the middle of a city where I have to worry about unloading my trunk and a cop seeing a marker and thinking "gun"... but not in the middle of a corn field either. City outskirts would be/is choice.
2) Pricing - You have to make money - and I realize that. This is a business...but you can't price yourself out of the market too. I'm not sure what a 2 bedroom apt, gallon of gas, pack of smokes, etc. run out by you - but keeping a case of middle-grade paint + entry at $75 ...is a comfortable price point. Reduce it for team practices...or offer volume discounts on paint. I stopped going to a local field because they removed the "airball practice discount" during the winter months.
3) Clean, plumbed bathrooms. Yes- the sport attracts kids. No - I don't want to shower or relieve myself in a bathroom with urine and feces everywhere. Having an attendant on duty is unnecessary- but having someone check it or clean it every 2-4 hours? Mobile bathrooms and plastic ****-houses? no thank you
4) Maintained fields. Going back to the "I left my last field because..." Their turf was ripping up off the concrete it was glued to, and they didn't appear to wipe down or clean their air bunkers. I know we're supposed to get messy...but there's no need to run up and hug a painted bunker. Its a statement of the state of repair of the field. Same goes with outdoor structures. If you can, aluminum/metal corner plates will help plywood retain the edge...and not look like ass after being shot a couple thousand times. Pressure washing structures between Saturday and Sunday open play adds an image of cleanliness to the field.
5) Lockers - Paintball culture...at some fields..is riddled with thieves. Locking my stuff up is pretty important to me.
6)Pro Shop - When you open - take survey of what markers people are using relative to your location. Adapt your pro shop selection and replacement parts accordingly. Doesn't make sense to stock MacDev parts if most people shoot Planet Eclipse. Also - buy replacement lenses based on your seasons/formats/indoor-outdoor ratios. Right now...I play at an indoor field. I don't need a mirrored lens...yet my field gets tons of them in stock.
7) there is no 7
8) If you have clothes - have fitting rooms. Its super valuable to be able to try things on before popping the tags off an item.