muh!
Give your dungeon a 90 percent kill chance...you will only be DM for two sessions
Always make up a good story, and never make rude mistakes, like letting appear people that died one hour ago (unless they are raised
)
Never feel sorry for a player. Faults they make are their mistake, and you only react appropriately
DEMAND a good background for the PCīs that makes playing lots more fun, and easier for you to DM
Never ever handle out to much XP, itīs the most costly thing in the D&D game...
Make sure every player can use itīs ability, so donīt create a non magical world, were magic is uneffective, if you have a party of four wizards
Read lots of fantasy books..if you havenīt read the Lord of the rings and the Silmarillion, you shouldnīt be a DM!!
Include humor in your dungeons.. the more fun the better..!!
God bless you and happy playing (Bob Ross saying)