It occurred to me that it might be helpful to new (and perhaps some old) filmmakers if I put down some pointers/opinions on how to make a good short film...
You can make a bad film out of a good script but not vice versa. Write a script. Then rewrite it. Then rewrite three more times. If a scene does not move the story forward, cut it!
If you can say something visually, do this instead of using dialogue. Dialogue should be the last thing you add to a script anyway. Take a look at my most favourite films.
Don't give a festival director or anyone a reason to turn off. Do not pace your short like a feature! No one cares about it like you do. You have to get into your story quickly.
Even if you can only draw stickmen, storyboard your film. Do this as early as possible. Let everyone see them and refer to them during the shoot. Be flexible but don't forget them!
It's tempting to use friends. Unless they are trained actors or just darn good you will be creating trouble. There are many talented actors. Do not be afraid to interview them.
Get people involved if you can but make sure they have defined roles. A cinematographer, 1st AD (or producer performing this role) and sound recordist are the most important roles.
Almost every film overruns. Experience helps but the more time you give yourself, the less mistakes you will make filming it. It will save you money in the long run!
Unless there is an aesthetic reason for your film to be handheld use the legs! But if you want to have that handheld look, don't go overboard. It can be offputting.
Much sound is added in post production. Even dialogue can be added. However, make sure you have a sound recordist on set to get the best sound you can. Unless you are skilled in sound mixing, bring someone in who can do this for you.
Along with sound, the most obvious marker of an amateur film. If you want your short to feel professional or "filmic" it should also be graded. Shots will need matching up at any rate.