People don't usually share outbound letters/emails because most people would send them out verbatim and only change the obvious things like the domain being sold. Eventually, these emails may be tagged as spam by the internet/email gods and end up in more junk boxes than inboxes.
Outbound letters/emails should be short and to the point, maybe 3-4 sentences max, (and NOT long-winded, run-on sentences lol), professional and polite with ALL of your contact info and full, real name.
Practice makes perfect.
The most important and toughest part, IMHO, is getting a hold of the right decision maker and setting the proper initial pricing, not the actual email/letter itself.