First of all, you should identify your objectives and also obtain your capital that you want to invest in buying an art gallery.
Hire an accountant and lawyer from the start of the process who will help you in dealing all financial and legal matters to make things smooth in buying an art gallery.
You should visit all art galleries in the town and try to know the cost of property and other relevant things. It will give you a much better idea about how much cost will it take to buy an art gallery.
When you select an art gallery that you want to buy, make sure that it fulfil all requirements of your business. Make a long term planning by keeping in view the extension of business in future.
Make sure that the art gallery is big enough to accommodate art classes as well which is one of the most lucrative way to earn a handsome amount of money from those who want to learn art.
You should also examine the structure of the art gallery and try to assess whether it is according to your requirements or not. If not, then try to convince the owner to make certain changes in it before making the payment.
Then take help from your lawyer and accountant to deal with the legal and financial matters while making the deal final with the owner of the art gallery.