A Good Dungeon Master must be a good Storyteller.
D&D can be considered also a tale told by many voices (Dungeon Master's and players') therefore the DM must be able to tell a story.
To have good ideas or to be a good actor isn't enough if you're not able to create a good tale that greatly engages your players.
Let's see how to do.
You are not a new Tolkien
Or the new George Martin or Jack Vance or whoever you like.
You are amateurs, with a little free time and usually with average skills (in a very few case above average skills).
They're are (or were) professionals, very highly skilled and experienced.
You cannot compare with them.
Forget to become famous.
Remember this Rule of the Good DM
The tale you create is fuctional to the game.
It does mean that if your players take decisions that go against your story, you must allow it, working on it in a new way or putting inside it those new elements which are created by players' actions.
Just to be ready to important twists you should follow this Rule of the Good Dungeon Master
Prepare only what is really essential
Prepare only what is essential but prepare it
A reaction to what written before can be: "Well! Then I won't prepare anything and I'll let the players decide everything" the so-called sandbox campaign.
This method has many flaws:
- it's based only on players' wits
- it's not suitable for shy players or with less fantasy ("What we are supposed to do?")
- it makes the game just a series of scenes without organization
But most of all, you have a story to tell. You are a DM and you want it.
Therefore create a story-arc but not get involved in details.
You'll create them with your players as the campaign will go on, by their choices and by your reactions to them.