Freelancer Proposal Writing Guidance

I’m a writer and translator who understands the craft of words but not yet the art of turning those words into winning bids on Freelancer. I need hands-on guidance from someone who already converts proposals into contracts here... (Budget: min $50 USD, Jobs: Article Rewriting, Article Writing, Content Writing, Copywriting, Editing, Proofreading, Proposal Writing, Technical Writing, Translation, Writing)