i'll start...
My TOP 5 BEGINNER DM TIPS
1. Have fun
2. Rules are a "GUIDE" It is the spirit of the game, not the letter of the rules
3. Yes, Yes But... , Skill Check (allow some auto success without skill checks)
4. Keep the story moving… set deadlines for resolution of problems/quests
5. Story over rules (Use a classic story arc with problem, action and resolution)
My Top 5 ADVANCED DM TIPS
1. Story First (Use story hooks that engage your players and link to thero backgrounds/motivations)
2. Borrow from books and films
3. Improvise when needed (improv npc dialogue)
4. Prep a few encounters beforehand but give your players agency the over order of encounters
5. DMs are storytellers. classic story arc (problem, action resolution).
2 BONUS TIPS.
1. Voices are cool but not every DM likes to use character voices and accents but they can add a lot of fun to the game and add to the immersion.
2. Recurring villains!
With experience and practice you will find what works for you and your group and find your DMing style.