Time can be a vicious enemy when building a business, especially in less populated areas. Clientele doesn't exactly grow overnight, and the fewer folks who live in your area generally means that there are fewer folks wanting their houses painted. I learned how to build my painting business while working for other contractors, both the right way and the wrong. I have never advertised, never had to.
In my opinion?
Do exactly what Rmichael has suggested[/u], because that is exactly how I did it, first in the Phoenix area and, about 4 years ago, again in the remote wastelands of west-central Minnesota. It took me less than a month to become overwhelmed with customers in Phoenix, closer to six months up here before I had to turn anyone away. If there is not a town of +/- 10,000 in your backyard, and with fuel prices the way they are, you have a challenge indeed.
I have friends here in town who paint for a living who also
barter for their services...One fella trades painting for everything from dental to meat processing. That is another consideration when trying to develop a clientele. Some people who would otherwise not be interested will often be eager to trade out labor or goods, and those people are also great word of mouth to get your name out there.
Good luck to you...