The whole set up of going through customs in the states is a little tedious in my opinion and time consuming, but here are my tips for flying internationally to make it less stressful.
When you are flying out of the states to an international destination, arrive at the airport two hours before your departure time. It seems like too much time but you have to check in and go through security and these lines may be long. Security will always takes time. Gates change, flights can be late, you just want to make sure to have enough time just in case something comes up.