DON'T:

...rely on your gut. Maybe for NOT choosing someone, but not FOR choosing someone. There are metrics for that.
...talk too much. We have two ears - one mouth for a reason.
...forget to listen effectively. Complement, acknowledge, maintain eye contact, nod, empathize, rephrase what you heard.
...make a decisions too quickly. If you choose the wrong person, it's not just lost salary - but lost time, opportunity, productivity. Spend 90-180 minutes in before committing to this relationship.
...just look at past experience, but past behavior Find out WHO they are - not just what they have done.
...hire for the future. Find someone to do THIS job, right NOW. Think about the 3-8 specifics of what a person must get done.
...overlook Google as a source to find what the best attributes of a good "product manager" is.
...get caught up being a CEO. You have to also be the Chief Recruiting Officer. Every. Single. Week.
...be afraid to stay in touch with people who are great even though they may already have a job already or you don't have a position for them. Situations change all the time.
...use a recruiter that doesn't know your culture.
...waste time when you see a misfit. Hit the red button and move on to the next!

Happy Hiring... and Firing