What are some things for new players to avoid? I am a new DM, I am preparing myself before I start a campaign with my friends. I am pretty nervous and the starter kit has kinda confused me about some things but I am getting the players handbook and DM guide so maybe that will help me clear some things up.

What are some things that I and my friends can avoid to make our experiences better? I want to let them have a fun experience and I want to be ready to be a good DM.