Many of my new concepts for books come out of a dream, yes. But sometimes they are there because something else sparked the thought. You can look for ideas deliberately or you can bumble through life with them cropping up on you. Personally I prefer to do both.
What can be the seed of a new story? Anything. I can’t think of a single thing that couldn’t have some story about it. Let me give you some examples of what I mean.
In a direct hunt I might pull out one of my esoteric encyclopedias and flip through and randomly stop on one that catches my eye. I have quite a few sources on things from ghosts to gods so I’m pretty much guaranteed to see something. And I collect these books so I doubt I will run out.
Another deliberate method is part luck, part perversity. I skim a book I don’t like. Sometimes it will frustrate me enough to bounce back with new ideas.
As far as the stumbling into enlightenment path goes all you need to do is experience as much as you can in as many forms as you can. And if you really like something, keep doing it. I have every purchasable episode of Mythbusters and I have watched most of them a ridiculous number of times. And I will watch them again. For one thing I have taken a break and don’t remember as much, for another it is always possible something will give me a spark.
Read fiction, non-fiction, watch movies, go to concerts, walk the dog, chat with a neighbor. The greater the variety of experiences you have the better. Get out and live. You will find words and ideas start to trickle back into your life and soon enough you will have the seed of a new book, new enemy, new chapter, what have you.
If you’re trapped at home during an Alaskan winter you can still learn and see new things all the time thanks to the web and thousand of streaming sources. Even social media can be a source of inspiration. Just keep exploring the world and learning new things, you will get the ideas you need.
If you can, get outside! Go to the forest, a park, a vineyard, the ocean. Look at the largest ball of twine or a statue made out of mentos (No idea if that exists or not). Take a weekend trip or just take the kids to a museum. The more you absorb the greater chance you have of letting something click.
But - and this is important - you need to be mentally rested. You need to give yourself time to think. And you need the energy to do it. Don't expect overnight results and don't push your ideas too soon. You might have a slow trickle start in your head. It can get frustrating to want to write, be willing to write, but blank on what happens. Just poke at what you do have and be patient. It will come to you.