No, I'm not swearing at you! BICFOK is Bum In Chair, Fingers On Keys - also known as BICHOK (hands, not fingers, on keys) - is a tried and tested way of getting words written!
Okay, I'm being silly, but really it does work. You're not going to write anything by procrastinating or by doing something else while you think about your story. Even if the first 100 words (or 1,000 words!) are nonsense or entirely unrelated to what you actually want to write, by starting writing at least you're getting something down, and you never know where it's going to go from there.
I used to use the 750 Words website to get me writing - you sign up to write 750 words a day and it sends you reminders to do it every day. I'd find I was writing about things I wouldn't have thought about writing about before - one day I write about the colour green, the next day it was about the weather, another day there was a boy setting fire to things. All these things weren't really useable in the sense of being read by anyone else, but they gave me practice at describing things and setting scenes which I wouldn't have had if I hadn't BICFOK'ed.
• Challenge for today - BICFOK for 15 minutes and see where it takes you!