You need to learn and work a lot. Have a lot of creative ideas that the public would like.As a writer has to write a lot, so does a screenwriter. This is the main thing. Write notes, synopses, treatments and, of course, scripts. Come up with different situations, disassemble them into details and describe. Make it as clear as possible, check if your writing is accessible to your critics. You don't have to wait for inspiration to write, it's not that profession. You should always be ready to write and do it systematically, no matter what you want.
