Ask HN: Advice for new project managers on new projects

In a few weeks, I'll be starting a new job where for the first time in my career I'll be in charge of a project starting from scratch. This will not only be the first time I'm involved in a project which has literally 0 lines of code written when I show up but also the first time when I'll be responsible for both structuring the whole project and actually telling other developers what to do. Basically, it's up to me to make sure the foundation everything will be built on doesn't suck.

Any advice on things I should think of or obvious mistakes I should avoid would be great!