I'm going to suggest a few processes, but please do scale each process to the size of the organization. Treat your processes like you treat your product - establish 2-3 internal customer problems that are actually worth solving, and solve them with an MVP of a process and iterate as you learn - don't try to introduce everything at once.
Team meeting: Reserve some time each week (PM only or PM+Design depending on team size) to look at the tactical work happening, what's coming up, concerns/help needed as well as to celebrate small and large achievements. As PMs we often forget to celebrate the good, so make space for this.
Expanding the team from 1 to multiple people comes with a set of pitfalls that I’ve learned the hard way. And many other factors such as Org culture, line of business, product lifecycle etc, have a telling effect on the type of pitfalls you’ll encounter, so take this with a grain of salt. Here are a few things worth considering -