I am not here to give you that tip.
I am here, however, to give you the advice I feel is crucial to any writer. If you don't follow this tip, you'll never reach your full potential. It's simple:
Finish what you start.
I cannot possibly hit you over the head with this hard enough.*
I cringe every time I hear a writer talk about how they have dozens of half- or quarter-finished novels, but nothing complete. "I just get distracted easily by new ideas," they say. They're making improvement almost impossible. Sure, they'll get good at writing beginnings. Maybe even middles. But what good is being able to write a beginning and middle if you never get experience writing endings?
And what about revision? If you never finish a book, you never have an opportunity to learn how to revise. In many ways, revision is a more important writing skill to develop than writing a first draft. Your first drafts will always be a mess, but revision turns them into something readable.
Think of it this way: imagine a piano player. She starts learning a song slowly, a few lines at a time. When she masters a line, she moves on to the next, and so on. Except that she stops halfway through the song, and starts working on a different piece of music, never returning to the first. What has she accomplished? Sure, she can play part of a song, but you can't perform half a song. Writing is the exact same way.
How, then, do you finish what you start?
It's easy. Trust me. First, you start a book. You keep writing. When you get another, "better" idea, you write it down, and then leave it alone. You don't start writing it--you keep writing the first book. Whenever another new idea comes around, you repeat the process until you're done.
As I've said before, the thing about "shiny new ideas" is that they're rarely as good as you think they are. Some ideas will seem awesome at first, but after you've mulled it over for awhile, you realize that it's not that interesting. If you stick to your current work in progress without switching to the new idea immediately, you allow yourself that time. You allow the new idea time to sit in your brain, and either fizzle out or solidify. If it solidifies, great. That's an idea you can use for your next book. If it fizzles out, also great. That's one more idea you don't have to worry about.
Working with the "I'm sticking with this novel all the way" mindset allows you to focus on one idea, thus giving it the attention and thought it needs. Novels, in some ways, involve more thought than writing. The more time you spend working on a novel, the more time your brain has to work through new plot ideas, patch up plot holes, and generally figure out where you're going with it.
Committing yourself to seeing one novel through to the end forces you to be critical of your own ideas. It forces you to weigh all of your promising ideas and choosing the one that resonates with you more than any other. It makes you put every idea to the test. This is another way to weed out bad ideas. When you finally choose the one idea to stick with, you know that idea is stronger than the others. If you know that, you're already a step ahead of anyone who abandons their current project for every flash of inspiration.
If nothing else, let's look at it from a publishing standpoint. If you ever want to be published, you'll have to finish your book. You an query an agent without a finished book, sure, but what happens when they want to read it? You won't have a complete work to show them. If you do get published, people will want another book. Your publisher and your readers will expect more, and that means you'll have to finish another book. And so on for the rest of your career.
I'm resisting the urge to go all caps lock on this. I could just end this post by writing FINISH THINGS, PEOPLE!
These past blog posts might help you:
How To Finish A Book
How To Battle Writer's Block And Emerge Victorious
The Shiny New Idea (And How To Hide It Under A Bushel Basket)
*Disclaimer: I do not actually want to physically hit you. Or Hulk out and smash around some Norse gods.