I would have made it a priority to travel more - especially abroad. Visiting places that are unlike your home can create such rich experiences. I wish I would have said "yes" to a couple of trips I passed up. Lesson learned!
Don't wait forever to share your stories, your writing. Don't fear that your creative work is not good enough. It is. In fact, people you've never even met will fall in love with your characters. Don't deny them the opportunity!