Whether or not you sign with a buyer's agent, your real estate agent will ask you a series of questions to find out exactly what type of home you're looking for and where. She will take those criteria and search the Multiple Listing Service (MLS) for matching properties.
Since most of the same listings are available online, do some searching of your own. Trulia.com and Realtor.com are two excellent sites for unbiased search results. Sites like ForSaleByOwner.com or Craigslist.org include private listings that aren't in the MLS database. Some listings offer virtual online tours and most include lots of interior and exterior photos. Online listings include useful information like how long the home has been on the market and stats about the local school district. You can even use convenient online calculators to estimate your monthly mortgage payment including property taxes.
Together, you and your realtor will assemble a list of the top homes to visit in person. This is the exciting part. Your agent will make appointments with the sellers' agents for showings. Most showings are done when the current owners are out of the house. In some cases the seller's agent is there to tell you more about the house. If not, the agent usually supplies a printed overview of the home's amenities called the listing sheet. Use the back of the listing sheet to take your own notes on the home's good and bad qualities. Bring a digital camera and snap lots of photos. It's amazing how quickly you forget a beautiful staircase or a clogged shower drain when it's your tenth house of the day.
If you find a few houses you like, return for a second or third walk-through during a different time of day. The neighbor's dog could bark all night or a freight train might pass a block away every day at 6 am. You might feel like you're bothering the owners, but it's worth the extra effort when making such an important long-term investment.