A very personal story. Don't doubt your work so much, have a little confidence! Besides if you're looking to improve just keep writing, you'll learn from experience.

As far as loving your best friend, I understand having other feelings rather than friendship (perhaps not quite as intense as love). It's best to tell them, I know it may be scary but you have to put it out there how you feel or they'll never know. It's horrible to be stuck wondering what 'could've been'. Besides, if she doesn't like you and she's mature about it you two can continue being friends. It's a little awkward at first but it gets better. Hang in there buddy!