Epistemology is about knowledge. Here's the most modern and advanced theory of how knowledge is created (or in other words, how we learn things):
First we come up with ideas. Some will be wild guesses, some will be minor tweaks to existing ideas, and others will be somewhere in between. The ideas will try to answer some question, solve some problem or improve something.
These ideas are going to contain mistakes. Some people have tried to find ways of coming up with ideas so the ideas will start out pretty good, and probably not have a mistake. That never works. It violates the spirit of fallibility.
We need to accept these ideas we've come up with may not be very good. There are mistakes and oversights and misunderstandings. That's why the next step is to look for mistakes.
Like brainstorming ideas in the first place, looking for mistakes is a creative process. It takes some imagination, not just mindlessly following simple instructions.
When we find a problem with an idea, what we do next is explain what the problem is, and why it's a problem. An explanation of a flaw in an idea is called a criticism. When an idea is criticized, then we know it's not good enough.
In reaction to criticism, we should look for a way to change the idea so it won't have the flaw anymore. If we can improve or fix the idea, that's great. Another thing to do is to criticize the criticism. If we explain a problem with the criticism, then we've learned something valuable (that that criticism is mistaken, and the idea is OK after all). Alternatively, maybe the idea wasn't much good, so we could tentatively give up on it.
Tentatively giving up on an idea means we retain the option to revisit it later. Tentatively is also the right attitude to believing ideas in general: they're the best ideas we know now, but we always keep the option to revisit them and change our mind later.
After we create ideas, and criticize them, hopefully we can narrow it down to one idea which is the best one we have so far. Then we can tentatively accept that idea. And that's knowledge creation. We know more than we did before. We improved our ideas; we learned.
Why does this process work? What if we narrow it down to several ideas and we aren't sure which to pick? Those are great questions; we'll come back to them later.