Picking up on the good advice above .....
Put a links page on your site - then identify local hotels, pubs, restaurants, camp/caravan sites, entertainment centres etc locate their sites and email their webmaster offering to swap links (perhaps indicating that you bring a number of visitors to the area who would be interested in such facilities and that you intend to build up a comprehensive 'gateway' for local viistors etc).
Also go to all the local facility providers (council, tourist board, chamber of commerce etc) on the same basis.
Identify any 'local' sites you can and approach on same basis.
Make sure your keywords/met-tags are comprehensive.
If that lot doesn't work (it is time consuming and fairly slow progress) then consider going to one of the search engine optimisation companies - they can be very good value (but go for one of the guaranteed performance deals).
I hope that helps.
TimS