Upload & Sell: Off
Having had two galleries in past years, if you want to try it then do so.
IF..., you don't mind sitting around waiting for people to show up. Unless you are doing studio work in the back or custom framing you will spend most of your time waiting for folks to walk in the door.
Many 'look' with their fingers so you need to be ready with cleaning supplies and towels. Some decide to straighten the pictures on the wall - you have to watch for this so they don't drop a print. Little kids are not supervised by parents too often and get into mischief.
Then, will you show figure and nude work? Anything graphic that might offend some in the community? It can cause problems.
Will you have school groups coming through? This can be a good way to get to parents with money to spend. Working with local schools to visit art shows can be a good way to increase traffic and expose the work to those you want to come back. Showing the images of local school kids and groups brings in many who would otherwise never set foot in a gallery.
How do you deal with the bums, homeless and wino types?
Small works that can 'walk off' can cause problems - so insurance covering exhibits has to be upfront with all those who put work in the gallery. WRITTEN contracts area must. You have to specify drop off and pick up times and hold to them. As soon as you get sloppy you start getting problems here. How do you handle sales - AFTER the showing? Folks who saw the image on your walls, contact the artist and wait til later to buy it so they can get a deal and avoid paying your commission? If you can't figure out how to handle this you will lose too many sales - but at times they may well be customers you are better off without.
Contests bring in a lot of folks. Recurring contests with a particular theme over a few years get known and garner visitors and entries both. A small fee for entry helps defray costs - and can help pay an outside juror who adds a bit of interest to them at times. Doing something highlighting local happenings or locations, in conjunction with the Chamber/schools/business/government can pay big dividends. Any kind of community involvement can mean more visitors and more sales.
One major help is a good mailing list. Well designed mailers, postcards and the like going out to clients, friends of the artists and other galleries and associations can pay off. Make sure they are well designed, clean and feature your logo/location prominently. If you can make them consistent so they are recognized as coming from your gallery every time they go out it will pay in the long term.
Good luck - it is a lot of work, long hours and often low sales.