Start with the idea or topic at hand and...
1. Step in and step back, step in and step back... For instance, if the topic is abortion, think about its ramifications on a specific 16-year-old girl, maybe an actual girl that you know. Then think about its ramifications for society.
Each time you add a new detail to your mental construction, step in and step back again.
This is a really useful process for artistic creation: (step in) what is the color of the grain of sand that the hero is rubbing between his fingers? (step back) What is the story I'm trying to tell?
2. Think sensually. Humans are sensual creatures: we live through taste, touch, smell, seeing and hearing -- also through fucking, fleeing and fighting. How can you tie your idea in with your lizard brain? Or how can you free it from your lizard brain?
The more abstract your topic is, the more it will benefit from sensuality. Is there a way to explore that equation or philosophical idea via sound or color? Do it!
Note: geeky folks in their teens and twenties have a very hard time with this. (I sure did!) They tend to want to live in a world in which everyone is a sort of Mr. Spock and the only thing that exists is pure reason. That's not the real world.
3. Think socially. Even before you fully understand an idea, try to communicate it to someone else. Take note of the parts that were hard to explain and the parts the listener didn't understand. Work on those parts. Brainstorm to come up with sharp examples and metaphors. Keep rethinking and rethinking how you communicate, even if you feel you have come up with the perfect explanation.
Note: PowerPoint is evil. When I was teaching, I forced myself to redraw the same charts over and over for each class, and I found that this process helped me refine them.
Also, collaborate! Get a core group of people to brainstorm with you, and, every once in a while, add a new person into the mix.
4. Do. If it's possible to do it, do it -- don't just think it. If you're sure you know what the result will be, do it anyway. The human brain plugs more easily into the concrete than the abstract.
When I work with actors, and they do a scene as if they're character is depressed, I often say, "Try it as if your character is happy." They often say something like, "That won't work, because..." I say, "You're probably right, but please try it, anyway."
The sometimes worry that I'm asking them to try it because that's secretly the way I want them to do it. They feel it's wrong, and they balk at trying it, because they think if they do, I'm going to force them to do it that way forever.
I work to calm their fears. I have no desire to force them into anything. I just have a profound belief that we don't know unless we try. And the more sure we are that we know, the more we need to try.
The only time it's no appropriate to try is when doing so is impossible or prohibitively costly in terms of time or resources.
5. Dig deep. Like a small, annoying child, keep asking "but why?... but why?... but why?..." Keep digging until you get to the foundation, the axiom, the article of faith, the unknowable. Note: the "unknowable" is not the same as "I don't know." What you don't know, you can research. If you can research it, you haven't reached the foundation yet. The foundation is what all your ideas lie on top of, so it's worth knowing what it is and what it implies.
6. MASTER research tools. Note: that includes but doesn't stop with google and wikipedia. If you've ever said, "I googled it and couldn't find the answer" and then stopped trying, that's a fail.
7. Learn more than you have to. If you're trying to learn how to bake bread, also learn how to bake cakes and muffins. Confidence comes from feeling some slack around the edges of your knowledge. If you feel like one question could slam you into a wall of ignorance, you're not there yet. Your knowledge needs breathing room.
8. Push yourself to failure. You learn from failure, as long as you push through it. Once you've mastered solving a particular kind of problem, you don't grow by continually doing those same sorts of problems. So add more challenges. You'll know you've added enough when you fail. And you only fail at failing when you don't keep pushing through it.
9. Play. Improvise, brainstorm, rap, rhyme, etc. Once you loosen the constraints on your brain, your subconscious mind will lead you to all sorts of interesting places. If you think "this topic is too serious for that," you're stuck in a rut and will be unable to come up with all sorts of ideas that would occur to you if you played in the mud for a while.
10. Take a break. Your brain continues to chew after you've stopped forcing food into it. Let it chew on its own for a while. If you're feeling brain dead, stop! Sleep on it. Or, better yet, do something totally different from the problem you're working on and THEN sleep.
11. Falsify your cherished notions. You're a Democrat? What if the Republicans are right? You're an atheist? What if there's a God? If you're closed off to ANY avenue of thought, there are things you won't think of.
Thinking is safe. Don't worry: you won't suddenly start throwing litter out the window just because you muse on the possibility that Global Warming might be a lie.
If it feels safer to you, imagine you're writing a science-fiction novel in which Global Warming is a lie. It's not a lie on our planet, but it IS a lie on planet Alpha Prime Zeta. Okay, what are the ramifications on THAT planet?
Do whatever it takes to push through closed mental doors.
Those things that you're super-confident about: slavery is evil; gay marriage should be legalized; one plus one equals two... Those thing aren't wrong. It's good that you're confident about them. But the bad thing about confidence is that it closes mental doors. That's kind of the point: "I don't have to think about that any more. I'm confident that I'm right about it." Allow yourself to say, "I know slavery is evil, but WHAT IF...?"
Your thoughts will never cause slavery to happen. Your thoughts are morally neutral. Stephen King is, by all accounts I've heard, a great guy, but he lets himself imagine people getting dismembered. And no one ever actually gets dismembered because of his thoughts. As long as you feel certain thoughts are wrong, you'll stop yourself from exploring many (possibly) fruitful avenues of thinking. You can't know if they're fruitful or not until you stroll down them.
12. Carry your ideas to their logical conclusions. "I think the sexes should be treated completely equally!" Okay, does that mean we need to abolish separate bathrooms for men and women in the workplace, just as we've abolished separate bathrooms for black people and white people? The goal, when taking your notions to extremes, isn't necessarily to poke holes; it's to test boundaries. In what cases does your idea apply? in what cases does it not apply?
13. Thwart your ego. Ego is almost always the enemy of thought. Most people don't let themselves "go there" -- "there" being to certain mental places -- because "I'm not smart enough."
Which means they're scared of getting their ego bruised by feeling stupid. Fuck that shit! That closes tons and tons of mental doors. You don't need to be smart to think about ANYTHING. You don't need to be right to think about anything. To think, you just need to think. It's okay to fail when you think. It's GOOD to fail. (See item 8.)
To fully embrace this -- and to vanquish ego -- you have to give up thinking in order to prove you're right, to impress your friends and to "be original." Those are all core human urges, and you're never going to rid yourself of them, but try to compartmentalize when your goal is to show off or argue vs when your real goal is to grow mentally or to solve a problem.
If you have convinced yourself that you never think to be right or come off as smart or win points, you're in trouble. We all do that. Admit it. Embrace the fact that you're sometimes going to do it. Know WHEN you're doing it, and stop doing it when it's not appropriate.
14. Think to serve. This is what most helps me thwart my ego. I'm a theatre director and an author. When I direct plays -- as soon as I start hoping the audience will think kindly of ME or be impressed with ME -- I remind myself that it's not about me.
It's about the PLAY. My goal is to SERVE, to serve the play, the story. The story isn't my servant; I'm its servant. If I'm writing a book, my goal is to serve the reader or the subject.
As soon as I redirect my energies that way, my mind expands.
Sites like ask.metafilter.com and quora.com can be great for this, as long as you use them to serve knowledge and not to win arguments, be right or look smart.
15. Don't ever try to be original. That's a mental dead end. When I'm working on a play, I sometimes get the urge to come up with something "cool" or "different." As soon as I feel that pull, I resist. My goal is to tell the story, not to get points for originality. Don't ever try to be cool or original unless THAT'S your acknowledged goal. If your goal is personal growth or problem solving, trying to be original will block you. And the irony is that, by not trying to be original at all, by just honestly working to tackle the problem, you'll wind up BEING original, because your work will be filtered through you, and you are unique in all the world.
Note: it's hard to apply a negative, like "don't be original." When I feel the urge to be original, I sometimes force myself to be derivative. If you're EVER stuck because though you know how to solve a problem, you don't want to solve it the way everyone else does, because that would be "copying," copy!
Short, famous version: "kill all your darlings."
16. Eliminate distractions. Every ounce of energy you're not spending on the problem is ... not spent on the problem. So are you wearing comfortable clothes? Is the lighting okay? Are there distracting noises? Do you have pens and paper and whatever else you need near you? It's a bitch if you have to stop working on a problem because you can't find a pen that works. I don't like to waste money, but I overbuy bens and paper and reference books. I want to be able to reach out and have whatever I need leap into my hand.
17. Study history. It's all happened before; it will all happen again. USE IT! By "history," I mean world history, local history or the history of some specific craft -- whatever is appropriate to your endeavor.
18. Identify rigidity and fluidity. What parts of the structure MUST remain fixed or it ceases to be whatever it is? What parts must be elastic or its not living up to its potential?
Think of yourself as a jazz musician, improvising on "Twinkle, Twinkle, Little Star." What notes MUST be played or the song gets so perverted that it's no longer the song? What parts can be improvised? Are you forcing yourself to hit nails on their heads? Are you forcing yourself to run willy, nilly between those nails?
19. Switch mediums. If you're thinking with prose, draw pictures. If you're lecturing, try miming. Try imposing arbitrary constraints: write about your topic, but force yourself to forgo using all forms of the verb "to be." See http://en.wikipedia.org/wiki/E-Prime
20. Take care of yourself. Exercise and eat well. Get a good night's sleep. There is no brain-body separation. Your brain is part of your body. It's a machine that requires tremendous amounts of energy. Feed it. Care for it. Love it.