You wanted Insane Troll Logic, so here it is.
Heroes are good right? and good people like to correct other peoples mistakes, therefore, if you tell your hero your plan and there's anything wrong with it, he'll tell you what it is so you can correct it.
The crazy thing is, this may just work, at least for movie logic. Say your villain doesn't have a flawless plan to conquer/destroy/gobsmackle the country/world/tristate area. I mean, those would be pretty hard, and a lot of powerful, smart and resourceful heroes would probably oppose you.
But what he does have is perhaps an approximation of what this plan would look like. And, a handful of other plans to partially beat, trap or temporarily disable some of the previously said heroes (individually). Then, the villain monologues, he tells the trapped hero his plan.
Now, one of two things will occur, either the hero will try to escape your trap to foil your plan or s/he'll smugly tell you your plan would never work, because.... (and here's where you take notes).
Ultraman: "So your plan is to use a gigantic lasso to pull the Moon towards the Earth, ha, that would never work, you'd need some sort of oversized tractor beam for that"
RaccoonMan: "HA, your tractor beam is impressive, but you'd need a power source no short of a fusion reactor to even make the Moon flinch"
Ms. Amazing: "Pff, nice fusion reactor you've got there, shame it will overheat and melt your whole plans away, you'd need to move the whole thing to Antarctica to stand a chance"
HumanFireplace: "Good luck with all the penguins not pecking at your electronics"
RedTailed Hawk: "Wait, so you got the penguin repellant??? ... I need to get out of this cell"
Now you only need to beat the last hero to win. But, hey, this is what you have been planing for. I mean all the other planning was basically outsourced for you. You just need to interfere with one hero long enough for your plan to work.
Most other villains probably fail cause they are worrying about two things at once. How to carry out their evil plan and how to stop the heroes from messing them up. You need only case about the latter. That means having at least twice the brainpower at your disposal.