Be professional. When you submit a résumé, don’t type it in ALL CAPS and please don’t avoid the caps lock like the plague. Know how to use it without looking incompetent. Write in complete sentences with proper grammar. Of course, there will be exceptions, but even with the exceptions, you must keep it professional. You’re building their view of you.
As someone who's been immersed in a number of online industries for quite some time, I know a thing or two about what it takes to succeed in this arena. However, just like you, I started at ground zero with little knowledge, but a great deal of passion. What I learned along the way were some invaluable lessons from failure that hurt at the time, but helped immensely in the grand scheme of things.
Take it seriously. Yes, you’re applying for an online job. Yes, you can do the work in your underwear, but that doesn’t mean it’s not a “real job”. You must treat it as such or they aren’t going to treat you as a serious candidate. You aren’t the only one who wants to work in their underwear. In fact, the competition online is likely higher than it is in your local area.