Re: How did you start out your editing career?

If you really, really want to get in to a professional editing position start first by learning to cut a good story.

Write a couple shorts (or rip off an existing story like Hollywood does)
get your friends to act in them (the acting doesn't have to be good)
obtain a camera (oftentimes, the local Cable Access channel will be willing to loan them out or get a cheap camera off of ebay)
shoot 'em
cut 'em together
watch them
edit them again
make 'em work and be effective stories.

Then, if you really want to do it professionally, look for smaller local TV stations with openings ("local" doesn't mean "local to you," it means "small, independently owned"). Those places tend to have a semi-high turnover rate because of the oftentimes low pay (so you'll eventually find one with an opening). You'll start out cutting commercials together and maybe you'll end up doing some longer-form stuff.

Lastly, learn everything you can about every aspect of the production process. There is a lot of cross-over type information. Learn about cameras, exposure, scene blocking, lighting, color theory...everything. The more you know and can execute effectively, the more valuable you'll be (and the more opportunities you have come your way).