Plan ahead when you want to see a specific movie, especially if it just being released. Buy your tickets online to save time so you don't have to stand in line. Also, many larger movie theaters have machines that dispense tickets similar to an ATM machine; these usually have smaller lines.
Arrive early as possible prior to the start of the movie. Waiting until the last minute to arrive usually means you will not have a good seat. Plan to arrive at least 15 minutes prior to the start. This gives you time to hit the restrooms and stock up at the concession stand before being seated in time for the previews. The earlier you arrive, the better seat you will get.
Go to see movies at theaters that have assigned seating. This works similar to making reservations in a restaurant for dinner. You tell customer service if you have any special needs and where in the theater you would like to sit. Of course, this type of movie seating is more expensive. If you really need to sit in the best seat in the movie theater, then go for it.
Call the theater manager to discuss paying a little extra to have the ushers reserve seats for you. This could also be helpful if you are planning to bring a large group to the movies.
Make your own home a movie theatrer and sit where you really want to, on your sofa. Wait until the movie comes out on DVD, rent it or download it and then pop the popcorn and press play.