Each movie goes through 3 versions: 1) the movie that was written in the script, 2) the movie that was filmed with the actors and camera, and 3) the movie as it was edited. “Images, facial expressions, and juxtapositions of editing should tell the story as much as dialogue, when possible” (Steven Ascher and Edward Pincus, The Filmmaker’s Handbook, 4th edition, 2012, page 531).
Production is assembling lots of possibilities, while editing is removing all the excess and getting to the core story. However, editing is also the addition of audio and special effects.
While editing you may find that you need to re-shoot some scenes (these are called pickup shots).
When completed save the file size and versions of the film that you need, such a DVD version, a high definition version for projection with a large audience, and a version for the web (e.g. YouTube or Vimeo).
Create posters and a trailer for advertising. Additionally, information or video on the actors and production is useful for "selling" the film to a festival (I like FilmFreeway.com) or contest . Depending on your goals consider, selecting some film festivals to submit to, presenting your film to your school and community, and posting to YouTube or Vimeo.