I think there are many ways to overcome writers block, depending on where you are with your book and simply how the rest of your life is going. Sometimes I think you just have to write, even if its 'rubbish', and as you write it can magically become "not rubbish." I had to write 2000 words a day for my second book to meet the deadline, so I just had to start typing. After 500 terrible words, sometimes another 1,000 would flow and then I could return and rewrite the initial terrible writing.
If I'm stuck with plot, and feeling the isolation that goes with that, I find going to a cafe really helpful. I think having the hum of life around seems to make that part of my brain work better, maybe I'm tricking myself into thinking I'm having a really nice time.

I think that walking or running is useful too. I have been seen scribbling things on the back of a receipt with traffic thundering past as suddenly I am unexpectedly inspired.

I'm not sure I have any particular writing prompts. Each morning, I tend to reread my last chapter and that gives me momentum to continue.

The most valuable advice I received as a young writer (about nine years old) was a friend's mother, who worked in publishing. When I said I wanted to be an author she didn't try and put me off, or say it would be difficult, but was wonderfully enthusiastic. Sadly, she died before my first novel was published and I was never able to thank her.