Pre-Production
Having a script is fundamental unless you want to do something a bit more improvised. Interpreting what is in the script and making it happen takes a lot of planning but it’s by putting the work in here that you will feel the benefits later on in Production and Post Production.
Unless you have loads of money, a lot of the films you make will be low to no budget. This is not a problem, as you will develop the skills quickly to become the master of getting something for nothing.