There is no rule on how to become a best-seller writer, there is no magic path that will certainly lead you to the success you dream of, but there are rules on how to create a good plot for your novel which is the first step to greatness!
Make sure you have a good storyline before starting your novel
Create an outline
Grab a pen and describe your main character, if you need you can even draw him/her. What is his/her back story? What is he/she going to do? What is the main agenda in your future book? This outline is only for you, don't forget it! Here you should write simple, with no twists, just the whole idea you have in several pages. Write straight to the point - from the beginning to the end.
Expand your outline
Add your other characters, give them a story, personality. How are they all connected? What experience they'll go through? Remember, you have to describe your characters in the story, think of a situation in which they will show who they are. Don't tell the readers, show them!
In this stage, you have to write the idea you have for every chapter and some important remarks. Take time for the little details and stay focused;
Fill in the Chapters
Write the story in each chapter. Think about the turning point, how is all connected. Every scene should bring more to the whole story. It should be captivating. And don't forget to check for inconsistencies! Give life to your characters - make them sad, mad, happy, serious, thoughtful, give them all the emotions a person has. Give each of them a specific personality - if you need you can read a bit of psychology or just think about the people you know. Give your story life, make the readers feel for the characters, make them smile, laugh... Every chapter has to move the story forward to the resolution.
The END or the resolution
Don't mislead your readers! You gave them a good story which they enjoyed, now it's time for a proper end. What is the turning point? How did your characters change? This is the moment when you should finish what you've started and ask your self if you are going to leave a door for a second book or you want to finish the novel for good. If you're writing series, make sure to finish this book with an end that satisfies the reader.
And a final tip from us
Writing a good story is not easy. It will take time and many do-overs until it's ready. Don't get frustrated, don't rush things. Don't be afraid to change your ideas! Your original draft will change a lot before your book is ready!
Also don't think it will be perfect and frankly don't wait too much before you finish your novel. There are no perfect things in life! Imperfection is the beauty of art! Don't overthink it!