I opened a shared office with someone I barely knew on the advice of other people I barely knew.
Don’t delay in creating a website. It’s the first place people look.
Don’t let the customers get to you, if you work in retail or the service industry. Just remember that they’ll be gone in a few minutes.
Don’t assume people know what you do!
Never give a lot of details about family, friendships. Be very neutral as it can be used against you in certain scenarios.
Not carefully critiquing my first work product before starting my second and third.