Buy your movie tickets to Toy Story 3 in advance of the release date by purchasing your reserved tickets in person, at the movie theater.
Most movie theaters allow you to purchase tickets up to a week in advance at the ticket counter. Sometimes this is not advertised and you have to ask!
If you can't purchase your Toy Story 3 tickets before the day of the release date, try to get to the theater as soon as they open the day of the release.
Most theaters open around mid-day. Use your lunch break to make sure your evening plans don't break a part do to a sold out showing!
If either of the first two steps is inconvenient for you, consider purchasing your movie tickets for Toy Story 3 in advance online.
Two examples of websites specializing in purchasing movie tickets online are Fandango and Movietickets. (See links in resources section below)