Answer:
By not stealing apples,and by always writing your your name on a piece of paper when your friends say hello to you.
Also plan ahead have a rough idea of where you want the story to go then let the players ruin it.
The more preparid you are the better you will think on your feet when the players want to do something different to your plans.
never try and rail road the players into doing what you want it will make it less fun if everything goes to plan
Dont be afraid to kill a charactor if they do something that would kill them you will get more respect if you dont fudge it so they survive some how ie lv1 attacking a dragon alone etc
make notes it helps you remember where you are and helps you remember the cool things your players did.
always make your NPC tough but killable cause if they are importent to the plot they will prob die early on.
Try to resist having your own charactor in the game who joins the party and helps out and give hints and does cool stuff it will annoy your players you can have recuring npc's that help the players but dont have one walking aroung with them.
If you dont like a rule get rid of it you dont have to play the game the way the book tells you its your choice if you want x or not in your game or maybe you want to add in y instead.
Enjoy it the idea is everyone playing has a laugh that includes you so dont forget it!