The point of trying to have true beliefs is to be happier, more or less through better decision-making. Thinking critically encapsulates not just evaluating beliefs but in making good decisions (both input and output) so it's just as important to have a sound decision-making process. At the rationality community Less Wrong they have good summaries of decision-theories and are trying to construct a universal one. That is: with the same information in the same situation and the same goals, everyone using this theory would make the same decisions.
Ben Franklin, ahead of his time in so many ways, was already thinking about decision processes. But he recognized a problem with human reason, which is that we're very good at building rickety bridges to whatever it was we already believed or wanted in the first place. Franklin himself was an occasional vegetarian, but when "confronted with the delicious smell of freshly grilled fish, he observed that the fish themselves disregarded his precepts by eating other fish and so deserved to be eaten. 'How convenient it is,' he said, 'to be a reasonable creature, since it enables one to make or find a reason for whatever one has a mind to do.'"
The article is in the Financial Times, and the author points out that a lot of business proposals are written with certain models to justify their requests; but that really, this is usually a ceremony that has nothing to do with the way businesspeople actually make decisions. (A more formal, ritualized way of building that rickety rhetorical bridge, except it produces fossil traces outside of our skulls in the form of written proposals and reports.) Unfortunately the author goes on to imply that this means there is no real universal decision-making method, which whether or not it's true, is a giant non sequitur here. Yes, humans are not built to get at the truth effectively and we tend to confirm our pre-existing convictions, but this doesn't mean that a decision theory is in principle impossible. The article is still worth a look.