The best thing to do in my experience is to just jump in and do your best. No matter what books you get or what tutorials you find, they're all going to say the same thing: Practice makes perfect. Just draw what you see, and do it every day, even if it's only for five minutes each time.
Be open to critiques, and learn which critiques are good and which are bad. "That sucks!" or "That's awesome!" are bad critiques, because they don't tell you what they like/don't like about the piece. "I think that your proportion is good" or "The colors just don't seem right, try blue instead." are good critiques because they tell you what you're doing right, and what you're doing wrong so that you can improve. Putting your art onto different sites, like DeviantArt, can get you lots of good critiques.
Learning from real life is better than learning from other art, because other art, even from masters, has the potential to be flawed in some way. However, that doesn't mean that you can't or shouldn't learn from other art pieces. Copying someone else's piece for the sake of practice - known as doing a study - is a great way to learn. Also, start off with simple stuff, like stilllifes. Grab a couple of random items from your house and put them on a table, then draw those. Build your way up to complex things like humans and animals.
Separate your learning experiences into groups that you practice for a while. For instance, you may decide that you really want to focus on learning to draw hands. So spend a week, or however long you need, just drawing hands. Then the next week, maybe you decide you want to learn facial expressions. This can also work for things like shading, proportion, color, cartoon style, ect.
Hopefully some of these tips will help you out. Good luck, and have fun learning to draw!
