A few weeks ago, Writing Excuses had an extremely hilarious podcast concerning writers and their excuses for not writing.
Although they may have taken it to the extreme, one has to stop, look back, and look at the things that have stood in your way of not writing.
"I'll just watch one more TV show."
"I'll just read this book, because I need to read a lot if I'm going to be a writer."
"I'll just outline or world-build this story a bit more, because I don't feel it's just right."
"When the kids are out of school, then I'll start writing."
"I don't think this is just the right story for me."
And on and on . . .
Stop the excuses. Sit down and write. Do it today. Not tomorrow. Today.
No, I told you to sit down. Don't get up and get a drink of water. Write. Write a page, then you can get a drink.
If at this point you keep coming up with excuses, then writing (or whatever it is you think you want to do) isn't your passion.