Dating your older home can be an almost overwhelming task. Where to begin? While you might start with the visual clues I am going to suggest another route, following the paper trail first.
Head to your local city hall or county record office and go to the building department. Any time that a building is sold or renovated there are records.
The tax department is also another good municipal office to visit. Taxes are not new; municipalities have been collecting them for a long time. Follow the paper trail of records back as far as you can. This gives you a place to start in your dating. You will now have the name of the original owner or at the very least probably a descendant of the original owner. Your deed is probably the best clue you have.
Talk to your neighbors. They may know about previous owners and some of the history of your home. If you are lucky they may be able to help you to make contact with some of the previous owners. Look for houses in the neighborhood of similar design and construction. By speaking to the owners you may be able to help date your home.
The next step will be to look for clues in the house itself. If you have an attic, go there and try to find a nail. Nails can be a great clue. These were not mass produced until around 1820 and went through many evolutions during the 19th century. Pull out one of the nails and look at it, is it a handmade nail? Then your house is older than 1820. If it is a mass produced one you may need to look at others. Be sure that the area you take the nail from is from the original structure, not a later addition.
What about a basement? Does yours have a dirt floor and brick walls or is it poured concrete? While the poured concrete may be a latter addition it is an additional clue. Does your house have fireplaces? More than one suggests that they may have been used as a heat source. Check the kitchen area for evidence of former stove pipes.
How is your home heated? Are there steam radiators? They were invented in 1852; this may be a helpful date. Do you have lights that show conversion from the original gas? Is there original wooden detail such as crown moldings, chair-rails, window frames and mantles? These can help not only date your home but identify the room's original purpose.
Don't overlook the exterior of the house. Roof pitch, type of roof covering and chimneys can also offer valuable clues. If possible look down into the chimney, the number of flues tells you the number of fireplaces. You may even uncover one you didn't know you had.
At the end of the day, there is no guarantee that you will be able to accurately date your home. All you can do is follow the paper and architectural trails and see where they lead. You may end up with a best guess scenario but the hunt will have been a wonderful adventure. Dating your older home is more about appreciating it than the actual date.