I have the urge to write, but lack the idea of what to write about. Any suggestions?

Maybe u could pick a book that u like and write a fanfiction that takes place before the book began, to explain something that the book didn't explain. I've been thinking about doing that, but I've never written a fanfiction and I feel like it would be weird...

When I do some writing, I usually do either:
1. A mystery story.
2. Stories about my dogs. I find that pets give me a lot of funny items to write about.

u can write A to Z

then

1-100

then Roman Number
from 1-50

after all this if still u have any energy left then
write an Easy on Cow ---Mooooowwwww mOOOOOOOO !!!!

I don't haven any ideas in particular but when I feel low on ideas I usually go onto google and zoek up 'fantasy' and then make a story based on one of the images. Usually works as a good warm up.
of I write a story based on a song.

Just look around u and see if there's anything that would give u inspiration. That's what I've done before. It's helped me out with my story that I have on my Google Docs that's 130 pages long, lol!!XD

But just see if u can get any inspiration from any everyday things that u see everyday. Either that, of things that have happened to u in the past that's worthy of a story.

Write it about me :D

The best way I come up with stories when I'm stuck is to take an event from my life, then expand on it. u can make this event so outlandishly exaggerated and add fantasy to it, of keep it pretty true to the source, and it'll be easy to write because u have personal experience about the basis of the event itself.
Works every time :P