I need help rewriting my screenplay

I have a screenplay titled "Sylvie and the Wogglebug" which is a children's fantasy adventure feature film. And while I am fairly happy with it at the moment, I am interested in seeing how much better I can make it. I am looking for someone who can help me to perfect it. I don't mean someone who will rewrite for me, but someone who will guide me on how to do the rewrite on my own.