Like any other job, before start, I will do this
- call 100 local clients (restaurants, spa centers, pizza delivery, blah,blah)
- if at least 20 of them are interested - Great! you are in.
- make nice and simple site
- start posting deals (that you got from your local stores)
- advertise your daily deal site in local newspapers, use adsense (again locally,etc)
Off course this is just in few words, but that structure you should follow, just scale it