Hi gr33n, and welcome to the forum. There are many different methods of defoliation, but it would probably help you to read this:
https://www.growweedeasy.com/defoliation
She says in this tutorial that many growers have various methods, and I haven't followed her tutorial to a T on my current grow, but rather I have been removing leaves on a daily basis since the switch to 12/12 12 days ago.
So read the tutorial:
don't take too many leaves all at once; watch your plants' growth and make sure they stay nice and vigorious in their growth;
remember that you can do a complete fan leaf removal at the end of week 3;
try to expose as many bud sites to light as you can; they will grow bigger the more light they get the eariler;
tuck leaves rather than snipping them now if you can;
don't allow leaves to sweat or lay on top of each other;
as Nebula says, make sure to leave enough leaves to power the stretch.
Watch the plants closely; it always takes me a little bit of time to look at her so I can figure out what needs to be tied down, what leave needs to be tucked or pinched off, etc.