A good email for cold emailing is that bring value. Think about it and try to propose something useful for your potential client. Try not to sell first, but just get an appointment or a call.
Open your sent emails and try to figure out the patterns. These are the base for your cold email templates. Then collect the most frequent follow-ups. At the end, you will have 1 main email and 2-8 follow-ups (we recommend to start with 2 at least).
Emails should be easy to read, with a clear value and efforts that you want from the recipient, and are easy to answer.
See also: How to add a good signature