I have gone to almost every indoor golf facility around me since about 50% of my time being interested in golf has been while there is snow on the ground.
There is not enough space on this forum for me to go over all of the problems these places have. Most of which are brought on by themselves.
Small upkeep like correctly patching holes in the hitting net if not replacing. Switching tees regularly(the one closest to me has the adjustable orange tee that goes into the rubber insert in mat)
The bar scene, only one of the places I have gone has a full bar, others are BYOB. The one with a bar is losing out on huge revenue by not sending someone around to see if people want another drink. My buddy, his brother and I went the other day and as soon as we got to the place they each got a beer, they finished and were empty for 5-10 minutes before my friend went up to get another round for them. Unfortunately since we were playing kind of slow we had to hurry a bit and he never bothered walking over to the bar for another round. When we left they went to another bar to get drinks, I couldn't believe it.
My advice to you is don't do it alone, each time I have gone to one of these places I feel like there owner/manager is doing all the work and just isn't able to see the full picture and make as big of an impact as possible.
My friend and I have toyed with the idea of trying to open one of these and I think we would make a good team since we look at things differently, that is key when there is a high risk of going under.
And lastly, don't hire a bunch of high school kids. They really couldn't care less if your customers are having a good time. They won't care that your not maximizing profits. Don't underestimate the fact that these are the people your rely on to get your customers to come back.