I would recommend (even to beginners) that they master the concepts of aperture and shutter speed, how they affect each other, and how they are used. Getting the exposure correct is the simplest task among other things. Maybe I'm misunderstanding the question, but you just need to make sure the exposure meter is generally in the center??
the exposure meter is good, but i also check the histogram as well. i try to look for a bell curve ideally, but in tricky lighting situations there can be lots of extremes. but still, depending on what you're trying to capture, the histogram will give you a good idea of whether it'll come out ok when you download it to your pc for editing or printing.
also, there is no single exposure setting for a given shot. you can get the same exposure using 2.8 @ 1/100s or 5.6 @ 1/25s. however, the image result wont be the same. you may see more bokeh with the 2.8 shot, and you may capture more 'action' with the 25s shot. you get a different type of exposure depending on your settings, and it really comes down to what kind of effect you are going for. ISO, in that sense, not only allows you to take lower light pictures, but also allows flexibility in the type of exposure you want, almost like ND filters.
bryan peterson refers to this difference in types of exposure as creative exposure. you can get the proper exposure in different ways, and it allows one to creatively capture a shot from a unique perspective that another may not necessarily see initially.
that said, simply getting enough light in is a simple task. use the light meter and verify with the histogram when applicable. but getting the 'creative' exposure that you want, that requires a lot of experience and an eye for unique perspectives.
