BCT did a good job in explaining our job. You really don't need a college degree to work line service.
As far as spinning props and such...well...basically just don't walk into them. A lot of common sense is in there. Don't chock a prop plane until they cut their engines. Though there are definitely some things that are a bit unnerving, but you don't have much of a choice. Plugging in a GPU into a Merlin where the socket is on the nose, and you're not more than 3 feet away from a spinning turbo-prop isn't exactly one of my top 5 favorite places to be. But as long as you're paying attention to your surroundings, or at least the stuff that will kill you, then you'll be fine.
Everything else will come with time and experience. You'll probably have at least a couple of different sizes of tugs and towbars. For me, it took a little while to be comfortable pulling around multi-million dollar aircraft in and out of hangars, but I got used to it and got pretty good at it.
As far as getting the job with no experience, my suggestion would definitely concentrate on FBOs that are run by county or municipal government as opposed to going up to Part 135 operations and the like. Most of the time, the private operations are looking for the people with at least a few years of experience for insuarnace reasons. KDPA is county-run, so there wasn't any problem with hiring me with no experience for insurance reasons. It just took knowing someone to grease some wheels in the right places to get me my job.
I'll tell you also, the more I hear about people who have trouble getting line jobs, the more I appreciate having mine, despite the low pay. Right now, I'm working two jobs...The ramp rat gig pays the bills, my other job pays for my flying. But it certainly plays hell on social life, and I'm single right now too...
Cheers!