Make a list of the addresses of the house(s) you love in your area and head to your local assessors office. As long as you have the street address, it is public information what the property taxes are and the contact information of the owner (much of this information is also online from websites like Zillow.com but it is not always as accurate as data from the Assessors office)
Once you have the contact information for the owners, do a Google search on the owner's names. Often times you can learn about what the current owners do for a living, what company they work for, etc.
Now do a Google search on the street address. Not only will this lead you to a map of the property, but you may see links to real estate listings for the property (sometime real estate agents don't take down their listings from their personal websites). Moeover, a Google search on the address may uncover mentioned of that property in "meeting minutes" of local government and zoning board meetings.
Now that you are armed with some background information on the owner and the property, begin drafting a hand-written letter to the owner. Let them know that you have always admired their home and that while you know the house is not for sale, should they ever wish to sell.... you are interested.
More and more people are choosing to sell their houses "For Sale By Owner" (or with the help of real estate lawyers) to avoid real estate agent commissions. In the letter, be sure to let the owners know that you are open to working directly with them to reduce the costs associated with selling the property. Many people fear the big "costs" asscoiated with selling a home so the more you can help reduce those costs, the more appealing you are as a buyer.
Describe in the letter what about the home you find most appealing. Never forget that people like to hear that they have good taste.
Empahsize that your interest is real and that you are willing to discuss a variety of ways to structure a deal that works for both parties. People decide to sell properties for many reasons: relocation, downsizing, divorce, etc. These are all major life-changing events and if you have expressed interest in the home prior to such an event occuring, you may be the perfect place in the perfect time.