If you want organic traffic then you have to build it as you would regularly do for any kind of site. Since you want traffic from Spain, you need to write original, unique content in Spanish. Well and regularly (even with the crisis there's opportunities but still I'm not certain that there's so much revenue here. Maybe because I live in Spain and I don't feel as positive as if you see things from abroad...)
And use the European Spanish, not the SouthAmerican. There's a huge difference between the different countries that speak Spanish, in the same way that there are significant differences in the use of English between US, Australia or UK. A Spaniard will notice ASAP if you use other kind of Spanish.
Also, if you have the chance, create a FB fan page using the Local business type and choose Spain (although you will need a Spanish address for this). Social media is always a good option to drive traffic but you need to maintain regular contact with your followers and for Spaniards, the best option is if you do everything in Spanish.
Obviously, if you host it in a web server in Spain that's a plus for Google, but I consider hosting location a low priority in my list of things to do.