Where possible listen but don't react, if there's stuff you need to talk about think about your words and how they sound and then raise it when you're both on an even keel.
Respect their autonomy when it's possible to do so.
Gently point to the feelings behind words and actions from very early on: yours; theirs; nearest and dearest; literary characters and so on, I think this kind of exploration and reflection helps develop emotional intelligence (in all of us).
Encourage/enable cross-generational relationships and then let them get on with it.
Be interested. Be neutral (where poss). Be respectful of them and in your communication on their behalf, i.e. with school. Don't hide your joy of being their parent. Humour, humour, humour - lots of and just for the craic.
Find a shared passion/hobby/interest but don't over-invest in it being shared - parallel I think I mean. We really love footy, I definitely watch more than my teen and have many stories from generations gone by but he's good for intel and stats and we both genuinely enjoy it.
Tell them how special they are and how much you care - be remembering, noticing and cheerleading (aim for non-invasive method but defo fall short).
Be proud of your own successes, own your errors, have good relationships with decent people. Find and be you amidst the parenting tool and let them find and be them.
I have to say the teen years have been incredible. Not plain-sailing, not simple but their development has also changed me and my life for the better.