Here is one example.
I find a potential company who could benefit from my domain name. I search people and try to find people who are responsible for "leadership" (CEO's, founders, managers etc.) in that company. If they don't have any leadership persons in LinkedIn, I'll try to find information about them at Google and contact them via email.
So, I'll sent a connection request to example Founder of X company. I'll include this message with connection request:
Hello xxxxx, I'm contacting you because I have xxxxxxx domain name for sale.
Regards,
Sami Ketolainen.
When the founder accept's my request, I send a message where I tell more about that domain name, how they can benefit from that domain name and how it can be used. There is not one right way to make a perfect sales pitch - You have to find information about the people and company who you contact so you have information about them and you can create really personal sales pitch and of course the sales pitch message doesn't look like copy and paste work.