It isn't likely that you'll move your house before putting it up for sale, so where it sits is where it will be appraised in relation to other homes and the offerings of the neighborhood. In appraising value, professionals consider nearby schools, shopping, and access or transportation to and from the home, as well as comparable prices of homes up for sale or recently sold in the area. Values in urban areas can go down based on vacant lots or condemned properties in the vicinity, and pricing in rural areas can decline depending on road access and land use nearby.
Even the amount of work your neighbors put into the upkeep of their homes has a positive or negative effect on your property value. Although you can't force neighbors to change the color of their exterior paint or tear down the rotting garage adjacent to your side lawn, you can ensure that any code violations, for instance the dilapidated garage next door, are taken care of before your home is appraised. Another preemptive move is to let your real estate agent and appraiser know of home improvements you've made. Keeping receipts helps with quantifying these improvements when it comes time to sell.