My way?
They get two pre warnings, then a mini out, and then a time out if it continues.
The first time warning is me telling them what to do right then (be quiet etc;)
The second is me telling the,m they will get a time out if they don't do it/stop it NOW.
Third time is a minute per year of them sitting on a kitchen stool. They don't have to be silent, but I won't talk to them. Ey can fidget etc; on it but if they actually move off it, time out starts again. If they move of two times, they go onto the full time out.
Full time out is very rare. It's for either, after a mini out, continuing the behaviour, OR if it's serious and I need them to calm down and think abou it for a longer time OR if they get off the stool etc; two times or more in the mini out. It usually doesn't come to it, in fact, I'd say last time I did it was ooh...seven months ago? It's 1min30secs per year so not exactly serious. My 4yo would get 6mins, my 6yo would get 9mins etc;
I do it if they're getting really het up and out of control of their emotions. I sit them on the stool and tell them it's their time to calm down and get away from it all. The mini is usually straight out sitting down, but they can fidget around etc; of course and if they're good after the mini out, then they get a sticker on their sticker chart or if they were say, having a tantrum, and manage to calm down on the mini out, they get praised loads and usually get a tiny treat of some form (like, a 10 pence type thing or some mummy time). It's not punishment, it's to give them time to get away from what's making them emotional, angry etc; So it's not something I'd do for lying, stealing or school stuff for example, but a mini tantrum, throwing toys or something....yes. At the end, we have a small talk about why had a time out and I usually ask them a few questions about why they had to go on time out.
Like I said, full time out isnt very serious, but again, rarely used. Depending what they do, it's either a straight however long of them on time out with talk at end, or it's a time out with a small phonics book or something like that. I've found it really helps to give them something to fiddle with or squeeze, my 6yo gets a stress ball (I got it as a birthday present but had no need for it and it helps her) and my 4yp gets a soft toy or something or some elastic bands even, or a squishy ball thing. I think it's hard for young kids to sit still and I also think it's unproductive. They MUST sit on that stool, but it lets out their emotions and their anger or whatever or simple rebelliousness by squishing, squeezing, pulling, fiddling etc; and is less awkward for them but still concentrates their mind and has the same effect.
It's their breakfast stool. It's got a cushion on it so is quite easy to sit on, they can swing their legs, whatever. Regardless of whether it's a mini or a full time out, it gets pulled to the corner (facing out of the corner though) and they can sit and fiddle or sit in silence.
They can talk if they want, cry in anger (but actual crying, I wouldn't let happen obviously...I'd get them off it straight away for a hug to find out why they were crying because it's no way a normal reaction so speaks of something else entirely, possibly connected or their bad behaviour....and if they're really upset, it's not right to keep them there when they need comfort. It's easy to tell the difference between tears of rage and actual tears of sadness), scream, whatever. The only rule is, they stay on that stool.