Follow all the advice given above as its very useful. Also, when carrying out link exchanges or submitting to directories, try and focus on UK based sites. Also, look at sites prefrebly with UK domain name suffixes and those who are hosted in the UK with UK IP addresses. Its quite a lot of work but thats the way to do it. I've done a fair bit of SEO for UK based sites only and thats the approach I've used. Its amazing when you look at your stats and see the majority of your traffic from the UK...... Good luck....
it is really hard to optimized a site on a specific location, I suggest to look for an affiliates to submit your site,or you can join forums on specific locations.