So many people talk about softwares, bounce rates, open rate, spam filter..is MailChimp better than poo? 5 lines, 8 paragraphs, 2 CTA, formating subject line..I call this BULLSHIT.
You are sending messages to people, not to lists, segments, contacts, but PEOPLE. People have emotions, they hope, they have dreams, but also fears. Your mission is NOT to make money, but to fullfil people's dreams.Help them, talk to them, individually whenever possible. Craft a solution for the most common problem they have. You won't even need to sell it hard, they will ask you to buy it.
It's harder when you start with unknown people, but OP showed a way to find and group people with similar interests.
So..be human, think as humans and humans will love you.