I'm a medical transcriptionist too and make good money. It's a real job, and you need training to do it, but it's worth the effort.
Start off small, don't try to take on more than you can handle. Its important that you are able to focus comfortably on something and get results from it since the results are what will encourage you to continue and not give up. You've already made a good first step, you're looking for advice in a forum (usually the info you get in forums are unbiased). All the best.
It is very possible, especially if you have the support of a mentor. Like what was said, it won't happen over night, but anything worth having takes work and persistence. The key is to follow the lead of those already enjoying success. You'll avoid all sorts of mistakes by following a top earner.
