I'm far from perfect but some things that seem to have worked well (and that I've done differently to my parents):
Parent the child you have got, not the one you think you should have had. My eldest has ADD and ADHD, both diagnosed very late and after a loooong fight. I wish I'd got him diagnosed earlier, but it took me ages to work out what was going on with him. The legacy though is that he knows I always fought for him and has his back. He told me last week out of the blue what a supportive mum he thinks I am. From a 15 year old, wow!
Let them have their say, listen to and understand their point of view, even if you know you won't agree. Encourage them to listen to yours too. When I was a child I wasn't allowed to speak up or defend myself- that was "answering back". It made me feel so angry and belittled, like I wasn't a proper person. self
Pick your battles. Be consistent. They don't have to do much around the house but they do have to clear up after themselves. Parents are not maids. They get a warning and if they don't tidy their stuff it goes in the bin. I've only had to actually do it twice (once per child).
Let them have some freedom.
Decent pocket money if you can afford it, but when it's spent, there's no more. We also don't but gifts or treats outside birthdays and Christmas. If they want something in between they have to save up.
Rudeness is not tolerated - financial penalties apply (See above). They can say how they feel without rudeness or disrespect.
Make clear that mum and dad are important too and deserve kindness, free time and a fuss made on their birthdays too.
They can confide in us about anything without fear of adverse reaction.
Honour their choices. Eldest decided to become a vegan a year ago. A massive pain as the rest of us aren't but we didn't make an issue of it because it was clearly important to him.
Give them privacy. We don't go in our teens room without asking/knocking and siblings aren't allowed to barge into each other's rooms. I hated the lack of privacy I had in my parents house. Likewise I expect the same courtesy when I'm in my bedroom or study.