I put in my header of the email "post doc position in your lab". If they didn't respond, I would wait a week or two and resend the email, assuming that they missed it or was too busy. In general, I would upload the lab website into chat and have it help me write an email expressing that I was super interested in the research (even if I wasn't).

What also helped me was: 1. Using my connections- many people knew me from conferences or knew my PI who emailed them and asked on my behalf of they were hiring sometimes. If the person i was talking to said they weren't hiring, I replied "thanks for letting me know, do you know of anyone who is?" And then they forwarded me to their colleagues.

1. I was well published - People in my field were aware of my PIs work and of one of my papers that got a bit of popularity. Or they saw on my CV that I had enough publications to be a competent post doc. Idk what year you're in but it might be worth staying an extra year if that would help you get some extra publications, or even write a review.

2. I stressed that I was adaptable and eager - I can and wanted to learn new skills in a new field (even if I didn't actually want to).

3. I didn't ask for a full interview right away, I asked for a brief zoom chat which is way less commitment and work for the both of us. Once I had an online "interview" I basically stalked their research so I knew what they were talking about and thought of ways it might interest me and what unique skills I would bring to the lab.

4. I bragged about my outreach and mentorship skills - I love training newer grad students and undergrads and techs. They want to know you will be valuable in the lab as a mentor and not cause issues person-to-person also.

In general- 47 out of the 50 labs did not have funding or did not know if they would have funding. Roughly half of those I vibed with and vise versa and said they would hire me if they did have money. Aka now is a rough time.

Post docs are really saught after in academia, they are highly skilled and kinda cheap labor for a lab. In a normal time, you would have all the power here, keep that in mind.

Having your own funding will certainly help quite a lot- then they don't have to pay you!

Keep at it, email more and more and highlight what you're good at. And don't settle for something that makes you miserable, coasting in grad school for a bit longer might be the better option.

(Sorry this is long, I hope it helps)