How to do SEO for 30 locations with one website?

[Casey]

It really depends on the type of company and the service. If its a chain of businesses that serve a local clientele there are several things you want to do. First you want to make sure that you have Google Plus (Formerly Google Places) locations with local phone numbers and addresses. Each of these pages will also need a landing page. You should have one main website and I suggest creating a locations silo with each location. An example would be:

http://www.YourDomain.com/locations/city...location-1
http://www.YourDomain.com/locations/city...location-2

Keeping all of the juice on the same domain is the best idea and setting up the location pages for each location will keep everything there. You can also register for local directories, etc., once you have all of that setup