I want to be sure you think about sound when making your movie. Sound is really important and a key element in increasing the production value of your film. If you didn't get great audio during principle photography that is ok. You can fix it in post. It's not ideal to ever fix anything in post and personally as a producer of numerous low budget films I think its lame. But the reality is that it happens. You can Automated dialogue replacement (ADR) or loop the dialogue after you have your rough cut. You get the actors to redo their line again and just edit in the better audio track. The other element is Foley. If you don't have good audio of objects landing or people walking you just replicate and edit that into the final edit. It's probably the aspect of post that is easier to do.
If you want to read more about Sound Design On Low Budget Films check out my Video Film School Site.
