You want to minimize the effort it takes one to reply. 1. An information-dense subject line 2. Tell them a soft compliment 3. A sentence about yourself 4. Say

You want to minimize the effort it takes one to reply. 1. An information-dense subject line 2. Tell them a soft compliment 3. A sentence about yourself 4. Say what you're up to 5. A very very very simple ask, don't make them think. Once they respond you can send a follow-up, at this point pretty much everybody will feel obliged to respond. My experience is only with cold emailing VCs, the reply rate was around 40% (including cordial rejections). CTR was over 70% (had a link in there).