Macroeconomics. My opinion and understanding used to be based on undergrad courses and a few popular blogs. I understood much more than the "average person" about the economy (so say we all) and therefore believed that I my opinion was worth listening to. My understanding is much better now but I still lack a good understanding of the fundamentals (because textbooks disagree so violently on even the most basic things). If I talk about the economy I phrase almost everything in terms of "Economist Y thinks X leads to Z because of A, B, C.". This keeps the different schools of economics from blending together in some incomprehensible mess.
QM. Still on mount stupid, and I know it. I have to bite my tongue not to debate Many Worlds with physics PhDs.
Evolution. Definitely on mount stupid. I know this because I used to think "group pressure" was a good argument until EY persuaded me otherwise. I haven't studied evolution since so I must be on mount stupid still.
Aside from being aware of the concept of Mount Stupid I have not changed my behavior all that much. If I keep studying I know I'm going to get beyond Mount Stupid eventually. The faster I study the less time I spend on top of mount stupid and the less likely I am to make a fool out of myself. So that's my strategy.
I have become much more careful about monitoring my own cognitive processes: am I saying this just to win the argument? Am I looking specifically for arguments that support my position, and if so, am I sure I'm not rationalizing? So in that respect I've improved a little. It's probably the most valuable sort of introspection that typical well educated and intelligent people lack.
One crucial point about Mount Stupid that hasn't been mentioned here yet is that it applies every time you "level up" on a subject. Every time you level up on a subject you're at a new valley with a Mount Stupid you have to cross. You can be an expert frequentist rationalist but a lousy Bayesian rationalist, and by learning a little about Bayesianism you can become stupider (because you're good at distinguishing good vs bad frequentist reasoning but you can't tell the difference for Bayes (and if you don't know you can't tell the difference you're also on Meta Mount Stupid)).
If you're successfully biting your toungue, doesn't that put you off "Mount Stupid", as the y axis is "willingness to opine on topic"?
A little knowledge is a dangerous thing, not sure what the official name for this particular cognitive bias is (feel free to enlighten me). Probably most of us can recognize that feeling of enlightenment after learning a bit of something new and exciting, and not realizing yet how far it is from the mastery of the subject. I suspect that learning the LW brand of rationality is one of those. (Incidentally, if the words "LW brand of rationality" irked you, because you think that there is only one true rationality, consider how close you might be to that particular summit of Mt. Stupid.) See also the last bullet point in the linked comic strip.
As an exercise in rationality, I suggest people post personal accounts of successfully traversing Mt.Stupid, or maybe getting stuck there forever, never to be heard from again. Did you find any of the techniques described in the sequences useful to overcome this bias, beyond the obvious of continuing to learn more about the topic in question? Did you manage to avoid turning Mt.Stupid into the Loggerhead range?
My example: I thought I was great at programming fresh out of college, and ready to dispense my newly found wisdom. Boy, oh boy, was I ever wrong. And then it happened again when I learned some more of the subject on the job...