On Trulia you can type in a complete property address and, should we have information about that home, we'll likely show comparable properties on the property detail page. You can also locate recently sold homes on our site under the Find Homes tab at the top of this page. This information is also available, specifically for your area, at the link below.
You want to find properties that sold recently in the neighborhood and of the type and size that the subject property is. For example, if your subject property is a 3-bedroom, 2-bath, single story, built in 1997 with a 2-car attached garage, 1/6 acre lot and no swimming pool, then your search criteria would be something like 3 bedrooms, 2 baths, built between 1995 and 1999 with 2-car garage. Then in your results you would either weed out the ones that have huge lots and swimming pools or else compensate (make adjustments) in your subject property price to account for differences.
You often have to look at picture and read the descriptions to see what upgrades, like granite countertops and ceramic tile flooring etc were made to the comparables. If the comp is better, then your subject will get a negative for the value. Say the comp had replaced carpet with wood floors in 1,000 sf of the place, but your subject still has carpet. Then starting with the comp price subtract the value of upgrading to the wood floors. Similarly, if the comp has granite and the subject has formica, subtract from the selling price of the comp to get closer to the expected selling price of the subject.
If you're subtracting more than about 10-20% of the price, discard the comp. It's not really comparable. Pools typically add 10% or so to the price regardless of value.
Once you have taken the average price of all comps and adjusted for differences, you should have your expected subject selling price. This is not necessarily your listing price.
You will have to consult someone, like a fellow Realtor, to enter the search parameters in your system, since there truly are many different input screens. Sometimes the local board is helpful for new agents.