I had an old comment answering this question, but it's gone now for some reason. Here's a summary though:

tl;dr: Get started drawing, do it a lot.

Short answer, practice, practice, practice. A lot. Doesn't have to be everyday, but have a consistent flow of work. And get people to criticize your work, and you'll learn more than you'd think.

Long answer, all of the above, but learn how to study the world. I can't explain it well, but luckily incredible resources for that.
Draw A Box is an incredible resource that has helped me more than I could've imagined. Lessons are neat and concise, and before you know it, you've improved 10 fold.
But Draw A Box doesn't teach illustration (at least at the first lessons), it teaches fundamentals. And if you just want to get into it without as much technical stuff, and/or digital paint, Ctrl+Paint is right up your alley.

But above all, still practice. Technical stuff is important, yes, and all the mumbo and jumbos of anatomy is important, also yes. But above all, nothing is better than practice.
I'm still learning myself, so take this with a bucket of salt, but I think this is what I do and think about.