pan of water, rolling boil, rolling not bubbling. Cap full of vinegar. Spin water in one direction, add egg to centre for 90s then remove. No need for the rest
^This
I would add that it’s much easier to get the egg into the water if you first break it into a ramikin or coffee cup.
Fresh eggs are a must really.
The rolling boil is important, if it’s going a mad boil they will fragment
Vinegar is good (you don’t taste it if you use a small splash), to a point it helps if your eggs aren’t the freshest
I never bother to stir the water, just drop them in at the edge, nice and slowly.
I also use a non stick pan with about 2 inches of water in it, and let them drop onto the bottom.
Source: I’ve cooked poached eggs (amongst other things!) professionally.