Search optimisation with regards to a geographically specific area is all about developing your business into a locally recognised and respected entity in a particular physical area.
Being well-known in the local community has an effect online, as often families, friends, colleagues, other businesses and organisations offer the online equivalent of word-of-mouth suggestions in social shares and hyperlinks directed to your site. These recommendations provide not only high conversion rates, but also a brand citation, and, hopefully, an unreciprocated link directly to your site from a local source.
What does this all mean?
Well, it means that the snowball begins to grow. The more people that know of your business, the more chance it will be recommended (providing you are offering a good product or service). The best case scenario being that this will continue indefinitely, while your products or services remain popular.
The problem is getting to that stage; becoming locally recognised in your geographical region; becoming a household name in homes around Kent, or Manchester. For this you need to look at your offline marketing techniques, and to combine on and offline efforts. You need to market your business offline, and you need to give a reason for your customers to find you or cite you online.
For this there are many techniques, though none as common as combined on and offline promotions such as a discount for a social share or Google +1, discounts for signing up to mailing lists, sending out flyers with links to online incentives, and so on.