Once you've scouted and chosen your locations, you need to ensure that you have the legal right to shoot there. If you are shooting on public property, you may need a shooting permit. If you are shooting on private property, you should have a location release. Depending on the location, you may also need a shooting permit to shoot on private property.
Special locations, such as military bases, federal buildings, airports, and cruise ships, will probably require more than just the simple permit issued by a city.
If you shoot on somebody's private property without his or her permission, you may expose your production to criminal penalties and civil liability for trespass, ...