One last tip: don't send her a photo of your phallus unless invited to. Short men are screwed when it comes to dating, right?Funnily enough most dominant women are looking for individuals.And while she may want to know how you look in petticoats she probably wants a guy who is a man.
But my height has only been as much of a problem as I’d let it be.
And there's nothing to be gained by trying to meet someone you can't satisfy or that would be inappropriate for you.
Aside from the checklist you really should have a few paragraphs describing yourself and your interests outside of D/s.
If her she calls herself Lady Sarah then your email should probably begin civilly and conventionally enough with "Dear Lady Sarah." Addressing her as Mistress implies a relationship with her that you've yet to earn. And if you've created a web page as I suggested above close your email with the URL.
State clearly and specifically what - if it was anything other than propinquity - that motivated you to write to her. More than just your cravings: that is just being pushy. Courting a Domme in certain respects is much like courting anyone.