I'm new to being the Dungeon Master. Do you have any tips for making a fun world for players?

Start simple and think big picture. When you're new, it's easy to get stuck on every little detail. My advice? Don't try to plan everything all at once. Focus on the main story you and your players want to tell. Decide the big things first - like will magic be common or rare? What are the main themes? Once you've got that, spend time making the first place the players will go feel real and lived in. You can build up your world bit by bit as you play. Trying to do too much too fast can feel confusing and limit your flexibility as the storyteller.