Ah, I've been there. Four months of grinding and barely two replies is brutal. When I first started cold emailing, I made many of the same mistakes. A few things that helped me turn it around:
First, check the baseline. What reply rate did the person before you get? If your industry doesn't respond well to cold B2B emails, maybe you need a referral-based approach instead.
Personalisation is key, but AI is garbage in, garbage out. Real personalisation means using signals from your leads - are they hiring? complaining? just fired a similar vendor? Did your manager actually review your email before you sent it?
Don't just ask GPT to "generate an email". You need warmth, a human tone, a clear value prop, and it must be short. Avoid the em-dashes that AI loves. I find it works best to have two layers - let AI set the tone and draft, then you go back and colour it a bit yourself.
How fresh are your signals? If you're just matching firmographics and the data is weeks old, that's your P0 problem. List discovery should happen on a cadence, not a one-time dump.
Last thought - can you speed this up? Even a 0.2% reply rate, if you can do it faster with tools (check with your boss), let the tool handle evaluation while you focus on referrals, community outreach, networking. Don't spend another four months grinding manually.