I freewrite.
When I am hit with a mental block it leaks into my other skills like my drawing and painting. so What I do is write on a timed stop watch for maybe 10 minutes at most, (I would start out at 5 minutes) but For these five minutes straight just right anything, In freewriting nothing has to make sense or work.
It can seriously be ANYTHING from one sentence to the next. Forget about the grammar and spelling and just let your mind right any words that are just sitting there.
This helps me, I think, For the fact that it pushes all of the thought that are just sitting on the top. kinda like greasy soup...all the fat beads up at the surface and kinda makes the soup taste like poo.
So take the spoon and sift all that BS out. Write with a pen take yourself out of the computer and away from the internet for a 10 minute gap to feel out these random thoughts. I like to go back and circle key words that stand out to me.
I have been using this method for about 5 years and it was suggested to me by my grandmother,(a very smart lady) and it doesn't always work right away, but it certainly gets my gears oiled up and ready to go.