Three most important stages of making a movie and my take on them

There are three key parts to making a movie for a director, the preparation, the shooting and the editing.
The preparation is all about idea generating, taking a story and turning it into a screenplay. To make a great movie you need a great script. If the script is right then there is a much better chance of making a great movie. The screenwriter has the most important role at this early stage of the production. I have worked with many great screenwriters in various ways. Sometimes the screenplay comes to me finished and polished and needs only to be translated by me from page to screen.
On other occasions I have found a book or an article I like and taken it to a writer and worked with them during the writing process. Sometimes I will write a short outline of an original idea I have and then collaborate with a writer to transform it into a screenplay. Screenwriters work in different ways too. Some prefer to take the idea and work alone for a while then present a draft for notes. We discuss the notes then the writer would go away again to work on a new draft. This process can go on for months, even years sometimes!
Other writers like to work with the director on a daily or weekly basis as they create the screenplay. Whatever the process is the rule persists that “you can’t make a good movie from a bad screenplay”. You can however turn a good screenplay into a bad film. The director has a big responsibility to make the best version possible of the writers work.
I like this stage of the film making process a lot. It is in some way the most satisfying part, creating the ideas and imagining the perfect version of the film. The production is very small in scale, I am working with just one or two people.
During the casting process the script can also change. Once I have heard the dialogue spoken by actors it can become obvious that the characters should be developed in various ways. The actor’s interpretation of each character is a chance to see a fresh take on the part. They come up with ideas that I or the screenwriter hadn’t thought of. However once the production prep is fully under way it is best to have a “locked” script. It isn’t advisable to change the script too much during shooting, this is inefficient and can cause chaos.
The writing and planning is over and the shooting starts. Suddenly I am working with hundreds of people instead of one or two. I love this stage too. I am surrounded by experts and talented people with a fantastic range diverse of skills. Production designers, cinematographers, sound recordists and designers, costume designers, lighting technicians, make-up and prosthetic artists, storyboard artists, special effects technicians, stunt perfomers……The list goes on and on. Now I am in charge of a what seems like a large factory mixed with a travelling circus. This the most spectacular stage of the film production but it also the most stressful. Each minute of each day has to be carefully managed as the costs of work of this scale are huge. That is why good detailed preparation is the so important. Everyone must know what is expected from them way ahead of time.
Then comes editing. The scale of production shrinks back down to a tiny fraction of the shoot. It can be just me and the editor for many weeks working with the shot footage. This is a great time to try things out and experiment with different ways of telling the story. Changing the order of scenes, creating the pace, eliminating unnecessary material. It’s a relatively inexpensive process so the pressure is off. Once the cut is finalised more specialists arrive in large numbers again. Sound editors and designers prepare the sound effects. A composer writes the music and musicians record the score. Sound mixers blend it all together. Visual effects and any CGI are completed and colour correction artists make the final adjustments to complete the film. The director is the luckiest person of all, the one who gets to see the story develop from an idea into a finished film.