(MONEY Magazine) – Whether or not you plan to sell your home, it's fun to find out how much money you've made. Your first line of attack--and the way most Americans stay on top of what's happening in their neighborhood--is open houses. Get to know what kinds of homes demand the highest asking prices and what renovations excite the most interest. Second, turn to the Web. Because real estate transactions are public information, you can find out what nearby homes have sold for at sites like domania.com. And you can get an estimate for your own home, but a warning: This price quote may be quite optimistic. You can contact a real estate agent through the site for more specifics. At a realtor site like century21.com, you can browse homes for sale in your neighborhood and sort them by price or by number of bedrooms and baths. And if you've been patrolling open houses, you'll be familiar enough with the properties to know how they compare with your own. --M.A.