What's your best template for cold reaching clients via email?

I recently founded my content writing agency, and I started cold-reaching clients via email. It is really a demanding effort and it takes a lot not to get frustrated with people not replying at all. Do you do cold outreach for your business? If so, what are your best templates and tricks to guarantee better chances of success? Here's what I've learned so far: * Prefer more customization in the email, never sending them in bulk * Provide some immediate value, like a freebie of some sort * Make sure you mention potential contacts you have in common or companies you worked with already for further social proof.