It's important to me to discipline my children in a proactive way. To some it may sound like total mumbo jumbo, but I don't believe that screaming, shouting or smacking work. It's the parent essentially venting their anger at their children.
So I seek to explain to them why their behaviour is negative, what impact their behaviour has for everyone involved. What behaviours I expect to see from them going forward, what will happen should they repeat the negative behaviour. Usually there's a punishment, but it's usually a letter saying sorry to the person(s) affected, plus a verbal apology. Other examples are electronics bans, or reduced/no treats that week.
I believe if you explain why they've behaved inappropriately, it actually sinks in. If you put it to them, how would you feel if someone did that to you, get them to really think why it's wrong, how you should behave how you expect others to behave. Then the apology plus or minus sanction, in the time taken off toys they can put effort into making a nice card, which is a nice lasting way of saying I respect you, I'm really sorry, it won't happen again. It's rare they repeat a bad behaviour, but if they do they know the sanction will be worse.
I've seen others scream at the kids, so parent is red faced and raging, the child responds with tears, I feel it teaches them that if someone does something wrong that's appropriate. The same with hitting, I don't agree with it because it doesn't achieve anything.
An example, one of my DC at a friends house on being picked up said something truly nasty. I apologised profusely and asked them to come with me immediately. I then explained this is meant to be your best friend, if they said that to you how would you feel. DC went out of their way to apologise ASAP and buy a nice present out of their pocket money to say sorry. Just so it doesn't leave their memory, I will say a few further times that I was really disappointed. My DC always get the opportunity to explain themselves, usually their reasoning can be slightly flawed so they'll be told why what they thought was wrong.
We start this quite young so it's consistent for both children. They generally appear to be remorseful. I will get the stuff they need to make a card, write a note, I'll sit by them whilst they're doing it.
DS misbehaved once in Reception, so he made a card with my help to say sorry. The parents appreciated it to. It shows the affected persons it's taken seriously.
The only time I've shouted, only twice to my recollection, was when they were in a world of their own and not paying attention to their surroundings. But it was a quick shout of name, to get their attention, tell them, be careful you're near a hot oven messing about, then explain, but no apology note. Just a reiteration of why they needed to be careful, plus suggestions to bear in mind.
I probably sound like a right Crunchy Mum. I would feel bad in myself for shouting, under no terms should they ever be hit. The sooner bad behaviours are addressed the better.