Keep it short. A clear subject, one line on why you fit the brand, one result you have driven, two content samples and a single ask. No life story. End with one specific next step and follow up once after about four days. Tight and specific beats long and polished every time.
The pitch structure
A good pitch is five lines, not five paragraphs.
Subject and fit
Name the brand and the fit in the subject so it gets opened.
One proof point
Lead with a single result, not your whole resume.
One clear ask
Ask for one thing, like a quick call or a rate request.