Thinking Skills

Please help to save the world (and improve your own life) by improving your thinking skills.
For a broader and deeper look at the subject of rationality, I'm creating a new page called A Guide to Rationality, from Basic to Advanced.
==Why?==
===Your brain is really bad unless you improve it===
Look at the scientific studies of average human thinking abilities and errors.  You don't want to be like that.
===Everything===
Basically every problem in the world is so much worse because of what people believe and how mediocre they are at thinking things through.  Get better at figuring out what is true.  Get better at problem solving.  Becasue we've all got problems that need solving.  And you can get better at doing that.  So why wouldn't you want to?
==What?==
===Get better at figuring out what is true===
This talk by Richard Carrier sums it up, here's the transcript and resources.
===Get better at choosing what to do===
To figure out what to do, there are two main strategies or methods:  "goal first", and "opportunity first".  These are just different ways of looking at the same thing, and should logically both produce the same result.  But sometimes using one is more efficient in a situation than using the other, and sometimes using a mix of the two is better than using only one.  Could be similar to the split between "outcome focussed" and "process focussed" strategies.
In all cases, having deep and extensive real world knowledge and experience can be indespensible.
"Goal first" method (called "problem solving" when the goal is to solve a problem):
#forget about solutions until you know what the goal/problem is. At least define what (precisely) is unsatisfactory, and why you don't like it, even if you can't tell what is causing the problem.
#imagine all possible forms a solution could take.  All forms, or as many as you (and other people you haven't contaminated with groupthink) can imagine.  That means, know all the variables that could be changed, and imagine changing each of them in different combinations.
#evaluate the options, and choose the best one
"Opportunity first" method:
#start by looking at what actions are immediately possible (opportunities)
#evaluate them, and choose the best one
With this method, you'll have to be careful not to be shortsighted, sacrificing long term goals for short term gains.
See also:  this outline of pursuing goals.