After experiencing this process myself, this is what I wished I had known prior to calling the contractor:
Check local ordinances before installing a fence.
Speak to your neighbor if the fence will be located along a shared boundary line. It is simply polite.
Clearly mark your property boundaries, regardless of whether you need to hire a surveyor.
Consider aesthetic appeal from both sides. You will live with this fence for years.
Document any agreements regarding the installation of a shared fence in writing.

Does the Finished Side Have to Be Facing the Neighbor?
Based on all of the research and experience I went through, I believe that the finished side of a fence is usually oriented toward the neighbor. However, it is not a hard and fast rule. Sometimes it is a law, sometimes it is a matter of etiquette, and sometimes it does not apply at all.
If you are unsure, and I know I was, I suggest leaning toward courtesy when possible. However, I would recommend making decisions based on your local ordinances, your property line, and a little friendly communication. A good fence may create a good neighbor; however, a good conversation creates an even better neighbor.

