There are some basic questions which can help us to separate different epistemologies from each other. I present these questions in no particular order as they are all equally important.

The first classical question is: can the world in general and my object of inquiry (which belongs to the world) in particular be known? Those people who are of the opinion that the world cannot be known are called agnostics and those who are of the opinion that the world can be known are called gnostics.
If you embrace agnosticism, you do not have much reason even to attempt to research any object you might be interested in, as you already have decided that you cannot get to know it; you can get at most to some shallow, whimsical impression of the object, that is, to some opinion about the object.
So if you want to research, you must be aware that you are already, at least in these circumstances, a gnostic.
Of course, even if you are a gnostic, you might still run the danger of becoming shallow, whimsical and opinionated, maybe even without you being aware. You have to be alert against this danger at all times. (See also [Plato, 1987, part 7, §6])

The second classical question is: does the world (along with my object of inquiry inside it) exist irrespective of my own existence? Those who answer this question in the positive are called realists and those who answer it in the negative are called idealists.
Linked to this question is another one: Can I get to know the world in general and my object of inquiry in particular ignoring myself, my biases, my very individual way of approaching the object? Elizabeth DePoy and Laura N. Gitlin focus exclusively but thoroughly on this last question. They call those who answer it in the positive experimentalists and those who answer it in the negative naturalists. This is not a classical classification, but can be used nevertheless.
You probably have already observed that the latest question is more practical, while the previous one is more about an assumed specific state of affairs. Both the naturalists and the experimentalists are quite keen to research; but before they even think of entering into action they have to decide whether the world is independent of themselves or not. They might want to decide this even if they never intend to reseach.

The third classical question is: can I get to know everything through experience or are there some things which can be known only by reflection, not merely by experience? Those who say that that there are things which can be known only by reflection (e.g., time) are called apriorists, those who think that everything can be known only by experience are called empiricists.
The sharp minds among you might infer already that an apriorist has to be necessarily idealist as the reflection is in somebody's mind. That does not mean at all, however, that all idealists must be apriorists.

While there have been quite a few remarcably intelligent people and even some geniuses who were apriorists, most of contemporary research you will encounter is empiricist.
As almost all research is gnostic and empiricist, the main difference among researchers is the polarity realism versus idealism.

Probably the best known realist epistemology and arguably the oldest in modern times is positivism. Jingoistic Brits pretend it started with David Hume although this Scottish philosopher rejected the possibility of certainty in knowledge. We can, however, say that David Hume is one of the forefathers of positivism as the much older René Descartes is. The real founder of positivism was Auguste Comte, although this word has been used first by Saint-Simon.
So what is positivism all about? Positivists are empiricists. Not only believe the positivists that everything can be known by experience but they also understand experience as evidence derived from senses. This evidence is the only possible in their opinion. The positivists have a innate aversion against speculations which goes so far as to make any interpretation appear suspicious to them.
The later positivists took quite a clear stance in the induction debate: they considered that you can prove that "All ravens are black" if you show that "This raven is black" and "That raven is black" up to the last raven. These later positivits even considered that induction is what differentiates a true science from a fake science.
The positivists also believe in historical progress: soon societies and men will become humane and civilised.

Karl Popper took issue with the positivists' attitude toward induction as the unique means to bestow authenticity to a science. While positivists are experimentalists this philosopher was naturalist; like the positivists he considered the normative approach the sole one appropriate to science. That is to say, Karl Popper saw scientists not being able to look at the world but through personally tinted glasses, so that the models they make of the world are bound to be tilted toward the preconceptions and expectations of their creators which become concrete in form of espoused theories.
As a counter-proposal to the positivists' inductive stance Karl Popper advocated a series of steps in the coming into being of a scientific theory:

1. paradox, that is, surprising observation of a phenomenon contradicting recognised theories;
2. hypothesis, that is, proposal of an explanation to overcome the paradox;
3. predictions derived logically from the hypothesis;
4. hypothesis test through observation and experiment.

Hermeneutics is a philosophy which started about 500 years ago by asking what is the correct way of reading texts. (You should understand by text and cultural product.) Hermeneutists are clearly naturalists and apriorists. The main focus of hermeneutics is the right interpretation of texts. Such an interpretation is based on "feeling" the text (or more generally the object of inquiry) or, to put it in another way, "getting into" the text (by intuition, we might add).
In the 20th century Hans-Georg Gadamer extended hermeneutics from the interpretation of texts to any knowledge aquisition. For him any knowledge is based on individual understanding; any bit of my knowledge can be explained by the way in which I understand. So, when it comes to get to know something, I have first to set clear my own understanding (including all my predispositions to specific and intimate biases, etc.) and then progress cautiously toward the object of inquiry, without losing sight of myself.