Stack Exchange is a growing network of individual communities, each dedicated to serving experts in a specific field.
As you can see, the network, and all of it's sites, makes it clear that the sites here are for expert questions and answers. This doesn't mean you have to be a master in your field to answer the question, but a lot of questions are fairly high level, no matter what site your on, and that's a good thing!
There are also many, many users on every site that are not experts in there field, but they're not exactly beginners either. This question is addressing those people, the "mid-ways" if you will.
Let's take Stack Overflow for example. The site is obviously the biggest and most popular on the network, and there is no denying that a very, very large majority of those questions are high-level, no matter what tag you're looking at. As a decent developer myself, I'm very intimidated when looking at the skill and expertise on that site! I began using SO when I was a beginner, worked my way up with the help of SO, and still find myself at the same level I was before, when comparing myself to those around me.
Now let's at Sports.SE. I've been a sports fan my whole life! I played many sports, and joined engaged in many conversations about several sports with people who I considered "stat-hogs". Yet, when I look at the people on the site, I'm blown away by the expertise.
Now, I can go on and on about how I feel stupid around SE-ers (trust me, I can), but that's not the point here. The point is, how can I, or anybody for that matter, make an impact, and maybe even earn some rep, on a site in which I'm not an "expert". In what ways can I still help a site, if I can only answer an extremely small minority of questions? And finally, what are the best ways to learn from these experts, without being completely intimidated?