More transfer medium than you think you should need. Experiment with the amount.
If you don't know what I mean, I'm talking about coarse-ground cornmeal or farina, the latter of which is a very coarse-ground wheat flour sometimes used to make a kind of cereal-mush kinda like oatmeal or cream-of-wheat—but it's also outstanding for this job; coarse durham-wheat can do in a pinch, but it's too fine to really be good at it, plus it tends to be expensive while farina's usually cheap (and so's cornmeal, but avoid the fine stuff, you want the coarsest you can get).
You put this on the peel before placing the stretched dough on it and adding toppings. Just spread it in a layer over the top of it. It helps keep it from sticking, which makes the transfer easier.
I've found different peels require different amounts. I had a shitty looking peel that was somewhat-rough, unfinished wood and it didn't require much. It got ruined (I'll spare you the details, but, kids) and I replaced it with a cheap but fancier-looking one I found on amazon, that's dark-stained, smooth acacia or some shit. It's awful. I need so much more medium on it to keep the pizza from sticking. I've thought about roughing it up with sandpaper, see if that helps, but haven't tried it yet—if yours is smooth-finished and you want to be a pioneer, maybe try that. First pie I tried to cook with that thing was the first I'd ruined in years. Still mad about it :-)
You probably don't need so much that you can't see any of the peel under it, though, even on one that bad. My better peel only required a light dusting, once I got my technique down.
Point is, definitely use that stuff, and experiment with the amount of that you put on. The more you have to use, the more waste and the more mess, so there's good reason to dial in what you actually need and not just pile a ton on every time, but you need some amount.
As far as technique: shake it loose over the sink (so any cornmeal or flour that falls off goes there instead of the floor or whatever) right before transferring to the oven. Just hold it level and shake horizontally, forward and back or side to side, until the whole pie's loose and moves freely. If you have spots that stick really badly, uh, try to lift it up and put more medium under it? This has never worked well for me, I've just gotten good at making sure that doesn't happen, but sometimes you can save it that way.
Then, when transferring into the oven, you need to hold it at an angle shallow enough that gravity alone will not do the work—too steep an angle, and it'll pile up when it comes off. You'll need the same sort of shaking action here, but because it's tilted a little it'll also slide off as it goes. Start with the edge of the peel way at the back of your stone, maybe just an inch or so from the back edge of it, and move it forward as the pie comes off, else your placement will suck and, in the worst case, some of it won't be on the stone.
If you don't know what I mean, I'm talking about coarse-ground cornmeal or farina, the latter of which is a very coarse-ground wheat flour sometimes used to make a kind of cereal-mush kinda like oatmeal or cream-of-wheat—but it's also outstanding for this job; coarse durham-wheat can do in a pinch, but it's too fine to really be good at it, plus it tends to be expensive while farina's usually cheap (and so's cornmeal, but avoid the fine stuff, you want the coarsest you can get).
You put this on the peel before placing the stretched dough on it and adding toppings. Just spread it in a layer over the top of it. It helps keep it from sticking, which makes the transfer easier.
I've found different peels require different amounts. I had a shitty looking peel that was somewhat-rough, unfinished wood and it didn't require much. It got ruined (I'll spare you the details, but, kids) and I replaced it with a cheap but fancier-looking one I found on amazon, that's dark-stained, smooth acacia or some shit. It's awful. I need so much more medium on it to keep the pizza from sticking. I've thought about roughing it up with sandpaper, see if that helps, but haven't tried it yet—if yours is smooth-finished and you want to be a pioneer, maybe try that. First pie I tried to cook with that thing was the first I'd ruined in years. Still mad about it :-)
You probably don't need so much that you can't see any of the peel under it, though, even on one that bad. My better peel only required a light dusting, once I got my technique down.
Point is, definitely use that stuff, and experiment with the amount of that you put on. The more you have to use, the more waste and the more mess, so there's good reason to dial in what you actually need and not just pile a ton on every time, but you need some amount.
As far as technique: shake it loose over the sink (so any cornmeal or flour that falls off goes there instead of the floor or whatever) right before transferring to the oven. Just hold it level and shake horizontally, forward and back or side to side, until the whole pie's loose and moves freely. If you have spots that stick really badly, uh, try to lift it up and put more medium under it? This has never worked well for me, I've just gotten good at making sure that doesn't happen, but sometimes you can save it that way.
Then, when transferring into the oven, you need to hold it at an angle shallow enough that gravity alone will not do the work—too steep an angle, and it'll pile up when it comes off. You'll need the same sort of shaking action here, but because it's tilted a little it'll also slide off as it goes. Start with the edge of the peel way at the back of your stone, maybe just an inch or so from the back edge of it, and move it forward as the pie comes off, else your placement will suck and, in the worst case, some of it won't be on the stone.