This is the fun bit! Organise a screening for a ‘select crew’. They need to be ‘critical friends’, not best friends. You want to know what they loved and what could have been better. Ask them what they thought of the 3 keystones of the film.
Go back to the drawing board, re-invent, play ‘what if’, add some twists and turns, refine the sound, and retake a scene. Then screen it again and ask for feedback before it’s finally film ready! Just remember the golden rule ... if it doesn’t add to the story … leave it out!