Ask HN: How to Sell to B2B and Agencies?

We are launching image processing SaaS app. How do I sell to B2B? I am looking to get first 10 users.

I sent about 40 emails and have one reply with 30% interest.

I am looking at email copy and asking B2B and agencies 15 minutes of their time.

It seems like no one uses email or no one replies from agencies?

Any tips and suggestions for this indie founder?