If you're serious about drawing comics then just study your favourite titles. Simple as that but studying alone isn't going to get you anywhere because observing and doing are entirely different things. If you're serious about becoming a great artist then draw from life and learn anatomy.
That's all there is to it but you need to make sure you're actually doing the work instead of studying. Don't even bother with those "How to Draw Manga" books because they're, for the most part, all garbage. That includes Crilley's.