Don't worry if something goes wrong, it all improves when you practise. So just draw, observe, make doodles, sketch and I'm sure you'll develop.
Plus, well, I support the idea of drawing from life, it's difficult, and believe me - my first tries were a real disaster... (now they are just a bit better

) but it really can teach you to observe and be attentive (<-is that English?). If you take up gridding - okay, it will make you feel more secure, which is also very important. But whatever you choose, the most important thing is just to draw. And you'll see that after some time your pencil goes where YOU want it to go.
Good luck!