Me too.. I would love to do some really detailed drawings but so far I can only do sweaters hahaha... I think its all about finding your own style, once you get that down, anything you create will have your signature on it. Even if its not actually signed, when someone knows your work they will be able to identify anything you do. That is what you should work on accomplishing, because even when drawing exactly what you see makes you feel proud of your work, it could never be really called your art, you didn't make it, you just made a copy of a picture.
Find your own style, and create things, that would give you lots of confidence. But definitely draw more, if possible every week not to be so harsh and say every day. You can practice with pictures, that's why I like doing fan-art, is a way of gaining skills, but I would never sell it as my art, unless its a request from someone you know what I mean? Another thing you could do is doodles... and that is one of the best ways to practice. Doodling is fun, but it has its trick. I learned that not long ago and it has enhanced my creativity like crazy... I recommend it.