Drawing from photos is a good way of training your brain to see things in proportion. Don't stop when you get close enough though. It's not enough to draw what you see, but you need to understand WHY you're drawing what you are drawing to make use of it. For that, you need a 3D understanding on the face. To do that, you need to simplify everything into simple shapes. Noses become triangles, heads become circles and stuff. Keep your hands loose at the sketching stage, and don't think while you draw. Just... draw what feels right, then flip it and see if it still looks right. Compare locations of things and don't get hung up on details till your picture developes to that stage. You'll get use to it. I wouldn't just subject till you've gotten the hang of doing one thing though. The idea of discipline is to practise till you get it right. Get humans right, then move to landscapes. They adopt alot of principles of construction that humans do, except they have distortions for being so far away. They're two totally different disciplines D:
Sorry I'm slow to reply at the moment. Computer issues and busy working on a comic >.< I hope you're having luck with your art. Remember to not be dismayed if they're not perfect straight out. Keep practising and looking for ways to make it right. You'll get there