There are three outreach principles that I always keep in mind when I create an email template:

• Offering. What do you offer to your link target? Is it a free content? Product or service? Sponsorship? This must be the first thing your link target must be able to see at the top of your message.
• Unique Proposition. How different your offer from other offers? If you're providing the same value then why would they bother to reply back to you?
• Call to Action. The end of your email template should get your prospect take any action (give you a feedback, answer your question, etc..). Be careful not to ask immediately for a link. It will just decrease your success/response rate.

The basic formula to create an outreach template is attached below (from SEER Interactive's post).