Kenji Lopez-Alt's method is the best I've come across[1]. His book is mentioned in the linked article as well, I've not read it but it sounds good!
[1]: https://www.seriouseats.com/2013/03/how-to-poach-eggs-easy-w...
[1]: https://www.seriouseats.com/2013/03/how-to-poach-eggs-easy-w...