Instructions
Talk to your neighbor everyday to maintain a healthy relationship. Neighbors who feel ignored will eventually move away from town. Likewise, if you do not play the game for a long time, the neighbor may have moved by the time you play again.
Write letters to your neighbor and attach gifts to keep the relationship strong. The letters should be simple and contain positive words like friend, gift or the name of your town. Gifts do not have to be expensive - a piece of fruit or a cheap item of clothing is more than enough. Mail the letters from the post office. As a bonus, you will often receive responses from your neighbor with gifts attached.
Maintain a pleasant town rating by pulling weeds and picking up garbage. Your neighbors may move if the town rating dips too low. Likewise, planting trees and flowers will help to improve the rating of your town. Check the rating at the post office for more information.
Avoid visiting other player's towns. Neighbors will often move from your town to a friend's town when you go for a visit.
Visit your neighbor's home to ask them to stay in the town if they are thinking about moving. The neighbor's home will be filled with cardboard boxes instead of furniture, and they will tell you that they are thinking of moving. Ask them to stay and they may reconsider. However, if your relationship with the neighbor is poor they will still move away. When a neighbor is planning to move, talk to them a few times to do some last-minute relationship building, which may prevent them from leaving.