Search and register on local news websites and local community forums. search for local business and website directories. Comment on articles and focus your keywords with your perfered local target, such as business names, street names, area codes, etc. although not proven, I assume some of these stregeties could be benifical.
If you want to rank well for a specific region, you have to show that your website is relevant for that region. To do this, you could get a bunch of links from websites that are hosted in that region or websites that are somehow related to that region. It may also help to host your own website in that region. Some people even believe that the location from which your domain is registered may play a role. I am skeptical about that. Another thing that helps is getting links from within website directories' regional sections.
Get backlinks from sites hosted in that country, have your site hosted on a server in that country, choose a country specific domain extension. Get links from the city, region (this will take some research) if you are focusing on london, obviously other sites focusing on the same will be of use, if their servers are located in london even better. Be prepared to spend some money.
Make sure you register for Google Maps. Once you get in the ten pack - try your best to get to the top of the pack - that will help your site's visibility.