Improve copy for client contact conversions

Native English Speaker required - please don't post if your first language is not English - I will not reply and you will waste a proposal credit.

I require a quick piece of editing to a letter I send to potential clients - conversions are not as high as I would like them to be and I need somebody to trim / edit / improve the copy to encourage conversion and reply. I would like a freelancer with sales experience.

This is a mail sent to clients who have requested contact - not cold calling.

Please outline your experience on email copy improvement.

I suspect that this is a very fast job - i think probably 30 minutes max is required to polish and tighten.