An interior and exterior photo of each house will surely jog your memory after you see a house. Be sure to mark the photo with the address of each house. Better yet, staple it to the listing sheet. A video camera is another excellent tool, as you'll get an even more accurate representation. Be sure to ask the listing agent for permission to take an interior photo or use a video camera.
Sellers are sometimes nervous about people recording their possessions.
You do not need anyone's permission to take an exterior photo. A second opinion. If you have children over the age of 8, they will have definite likes and dislikes about a house. They should be included in the process, perhaps at the second or third showing. Invest in two three-ring binders or one large one with a divider in the middle.