People are always asking me where I come up with my ideas lol. The thing is, I'm never looking for them--they just pop into my head.
For instance. My first book, Cursed Blood, came to me through a nightmare that I had which came about because of my real life and it took writing the book to figure that out!
A chapter in Peterson Estate book 2 (in the process of rewriting now) came from when I was playing a game of cards with my hubby and his friends. The queen's face had been rubbed off due to being handled so often lol. There's something to looking forward to lol. You should read the first book when it comes out, very interesting lol.
You have to let your mind be open to accept ideas. Your imagination should run free. Don't set boundaries for it. The boundaries can be used for the writing itself, not the imagination.