I've been writing stories for a long time.. and recently I've had a hard time going through to finish the story because I have another idea. So I stop the story and start another one. I cannot stick to one plot line. Any tips?

It's not bad to want this, but totally unrealistic and rather naive.
Just getting a book published is incredibly difficult.
Even if it was published, the chance of it being so good that anyone would want to have it adapted into a screenplay is remote.
And if it was made into a screenplay, the producers (the ones who put up the money) would want a professional director to direct it. Allowing the writer to be anything more than a co-director or assistant (which is more a courtesy than anything active) would be insanity.
It's the same with actors. They'd only use real, professional, trained and experienced actors. No-one would risk millions of dollars by using an amateur - even if it was the writer. The best they would agree to would be as an extra.

Try to be realistic and understand that even one of your goals is unlikely.
Chose one of them and work really hard. If you have huge talent, you might get somewhere.
But you're being very naive about how hard all of those careers are to get into - even at a very basic level.

Good luck!

does heroine ends up with main hero?? please I want to know?

does any one know ending of Korean internet novel syndrome by guiyeoni I have read up to chapter 46 but just tell me does heroine ends up with main hero?? please I want to know

If you aren't a drug mastermind yourself or living with one, of course the only things you will know are what you've seen in TV and movies (about 2/3 of which won't be accurate anyway).

The ways to remedy that are
1) Write what you know
2) Write what you don't know and research the heck out of it. Read about it, interview experts, do hands on research. (If your goal was to write high fantasy with a lot of sword fights, for instance, you should learn both fencing and stage fighting.)

However, in this case, I'm not going to suggest you set yourself up as a drug lord--it's illegal and dangerous. And the only books you're likely to find published on the topic are skewed to a law enforcement perspective, so it's a tough topic to research.

It's normal for new/young writers to fall in love with a TV show, movie, or book series and write derivative stories. (Some even write fan fiction). The more you read, the more influences you'll have and eventually your own voice and genre will emerge.

It's far more important to continue writing steadily than to worry about being derivative. Keep reading a lot, keep developing your craft, and by the time you're good enough to be published, you should have moved on to other stories to tell.

There are many ways, but each one is contingent on the reason for doing so. Why do you want to make the ordinary dangerous and exciting? What's your motive?