That's one of the best newbie questions I've seen. Just realizing that you can be overwhelmed will help prevent it.
Just accept the fact that there's no real secret, don't try to read every blog, visit every forum/site, buy every ebook looking for something that doesn't exist. Making it in this business takes work.
The two most important things are time and money, the more you have of one the less you need of the other. You may have to do most of the grunt work when first starting out, but you should begin outsourcing as soon as you can afford it.
Here's what I recommend you start with.
The basics of setting up and maintaining a site, hosting, domain name, etc.. Learn some html and css, you don't need to be an expert but it'll help when you want to tweak a page layout.
SEO basics. Title tags, meta description, keyword density, proper backlink building methods, sitemaps, etc.. Google Aaron Wall
PPC basics. Keywords, adgroups, keyword groups, ad copy, keyword research, difference between content and search networks, knowing the difference between a landing page and a regular webpage. (see Perry Marshall, MindValley Labs, Google Adwords Help Center)
There's much more but that should get you started. You'll get the most education from experience, don't be afraid to try/test new (legal) things (unless you decide to go BH, then I guess you wouldn't care), but don't just jump into PPC and blow your wad before you realize that you were doing it wrong.
The most important thing is to just do something, don't spend all of your time trying to learn. Build a site, start a blog, set up a phpbay store, just do something.