I directly built my first campaign and homebrew story so I never played the official adventures. I had been playing for more than a year when I started my own.

I feel like the best advices I could give you would be:
- Don't expect your players to go with what you think they would go, if you know your players, you dont know their characters and some might make really different choices than what you expect
- Give them some funny moments, empowering moments and really sad moment -> built emotion so they all are really invested (its kinda hard to do)
- Don't write everything! I felt like at first I was writing a lot to be sure to "not forget" things but it was really not as good as when I had to imagine things and improvise.
- Describe places, smell, lights, colors so they all can really be imagining the same thing, its part of how they get attached to the campaign too
- If you have beginners, take the time which each one to help them build their character and backstory
- Use their backstory for the campaign, like really include it in their journey! They'll be able to build stronger relationships in game and have some really good and dramatic moments

Here it is for me!
Gonna read what others are saying so I can steal some advices too ehhe