One of my favorite sales trainers (Colleen) used to tell us: Credibility, Benefit, Close. Always tell they why you are credible (worth their time), always tell them how you can help them or their client, and always ask them for something (a follow-up call, a meeting, a signed deal!).

So adapting this to email here is my sure response:
1. Your direct supervisor (or client or the person who pays you) told us to talk (credibility)
2. I have a unique exclusive media product that can hit your objectives (benefit)
3. Can we do 15 min intro call? (close)

Now, if you can’t get that direct supervisor/client to refer you then you need to find other ways to appear ‘credible’ and worth your prospective client’s time.

Credible building email ideas include (strongest to weakest)
1. We’ve had success with your direct competitor and can share general best practices (don’t be slimy;)
2. We are experts in your industry (detail detail detail – to make them believe you)
3. I heard you speak at a conference and loved your insights and wanted to ask about more details in x, y, z.
4. I saw your post about x project and loved it and I think we can help…
5. This article about x project is applicable to what we do for companies like yours.

What other ideas do you have? Please share!

The tips below is from a Forbes article:
How to get someone to respond to your email?
9 Surprisingly Simple Ways To Get People To Respond To Your Email
Ask For A Response In Your Subject Line. …
Change The Subject Line When The Topic Changes. …
Don’t Skip The Greeting. …
Start Your Message With A Clear Request. …
Stay In The Sweet Spot When It Comes To Length. …
Use Third-Grade Language. …
Use Emotion. …
Use Rich Text.
See article: https://www.fastcompany.com/3058316/9-surprisingly-simple-ways-to-get-people-to-respond-to-you