I don't know that I can say I'm particularly good at this, but to the extent that I do have any original / good ideas, I think a big part of it is this:

1. Know at least a little bit, about a lot of stuff.

2. Know a lot about at least a few things.

3. Constantly trawl for new "stuff" (eg, read books, magazines, the web, watch documentaries, etc.)

4. Think about how to combine different bits of the "stuff" you have in your head. Take notes, write down lots of ideas, even if they're dumb at a first glance. Keep chewing on things, and eventually the penny drops and you see some connection between things that makes sense.

5. Related to that, and I don't do this well enough myself, is "spend a lot of time thinking about the kinds of problems people have".

I've read a few books on creativity / innovation / etc., but I'm not sure I can say any of them specifically helped, although a few of the ideas may have been useful without my being consciously aware of it. I read some of the Lateral Thinking book and I vaguely recall thinking it seemed somewhat useful. YMMV. https://en.wikipedia.org/wiki/Lateral_thinking

I also recommend Alan Kay's video series on "How To Invent The Future".

Part I: https://www.youtube.com/watch?v=id1WShzzMCQ

Part II: https://www.youtube.com/watch?v=1e8VZlPBx_0

Another thing: I think sometimes ideas come out that are "ahead of their time" and seemingly die on the vine, or just get left behind. But sometimes when the environment changes, those ideas become ripe to get re-invented. There's a book title Rethink that sorta deals with this idea. https://www.amazon.com/Rethink-Surprising-History-New-Ideas/...

Anyway, I think there's some value in reviewing "out of date" literature on various topics, and look for things that seemingly died, that may be ready for you to pick up and run with.

Finally, there's this book: https://www.amazon.com/Intuition-Pumps-Other-Tools-Thinking/...

I bought it a while back, but honestly haven't had time to get to it yet. But if seems like something that you might find interesting.

One idea you could try is this: take an "old" idea and "remix" it, improve it, etc. The book Rethink[1] has a lot on this. And it makes sense.. in computing, things really tend to go in cycles and what's old is often new again. Take Neural Networks for example. This is an idea that's so old it's practically archaic. But add some new ideas on training (backprop, discovered in the 80's or so), along with hardware advances due to Moore's Law and the advent of the GPU, as well as the surge in data volumes enabled by the Internet, always-connected devices and advances in storage technology, and BOOM... you have the hottest topic in the world today.

So go back in time... read old computing books, read old issues of InfoWorld or Network Computing from the 90's or early 2000's, or find some old issues of Byte magazine on Ebay, and mine through those... and find an old idea that can be combined with some new advances or new technologies, to make something that's mondo radical.

[1]: https://www.amazon.com/Rethink-Surprising-History-New-Ideas/...