What are the top 3 potholes to AVOID when establishing or building out the Product Marketing function at a company?

I can't think of three good ones right now, so I'll give you two of my favourite:

1. Saying yes to everything
   When you come in as the first PMM, people are going to be throwing projects at you left and right. It's easy to say yes to everything, after all, who wants to say "no" in their first month on the job. But it's important to set the precedent that everything can't be your top priority right away. At Klue, I'm hopping on calls with as many people as I can and asking them for their top priorities/asks for PMM. At the same time, I'm very transparent that I'm building a project board of every priority that I'm going to be sharing internally. Then, with my boss and some other leaders across the org, I'll work to prioritize the list so everyone can see what's going to be worked on, when, and why. 
2. Dissapearing into a hole
   A solo PMM is naturally a very autonomous role, so it can be easy to slink away into a dark hole while you work on a big project. Don't. Everything we do as PMMs should be collaborative, especially when you're new to an org. You should be getting feedback and iterating often. If you keep projects to yourself for too long, you run the risk of wasting huge amounts of time on something that doesn't work. And people will notice.

• Do not hire more people until you have a clear charter for the team
• Make sure you align with other cross-functional teams as you build your org design so that your team has clear partners across different functional - otherwise, this almost always fails
• For smaller, newer PMM teams, avoid hiring people that have a very niche focus. You will benefit more from building and growing a full-stack PMM team