If you say popular area, are you referring to a area with a lot of Bitcoin merchants or a area with a lot of Bitcoin users. Operating a BTM has a lot of challenges and it is very expensive if you do not have a lot of Bitcoin adopters coming in and out of your shop.
Also make sure you are listed on some of the online resources once your BTM is in operation. People should know where to find you, once it's done.
Example :
http://www.coindesk.com/bitcoin-atm-map/