A lot of the people who do bigger HITS, like for Casting Words, use a foot pedal with Express Scribe (free software). If you are transcribing something into an editor, like Word, you can also use a word expander. It's a huge dictionary that you can edit, and it'll allow you to type shortcuts. For instance, maybe it would be set up that if you typed evtg, it would expand it to everything.
I like the small ClariTrans jobs, but the style guide is so completely different than that of CastingWords. I suggest that you find a company that you like, work really hard on memorizing their style guide and checking it against your work until you are satisfied. Then, you can really start to move along at a brisk pace.
Best of luck to you!