Author has written 4 stories for Underland Chronicles, Push, Inheritance Cycle, and Harry Potter.
Más sabe el diablo por viejo como por diablo.
Humor the opinion of a somewhat seasoned writer: a great way to be critical of yourself is to study other (and especially published) authors' works. Good, bad, everything in-between, you'd be surprised about the impact it can have. Some suggestions for your indulgence:
If you enjoy fantasy (especially of the epic variety), read:
A Song of Ice and Fire, by George R.R. Martin
The Malazan Book of the Fallen, by Steven Erikson*
The Lord of the Rings, by J.R.R. Tolkien
The Kingkiller Chronicle, by Patrick Rothfuss
If you enjoy intelligent drama, read:
Anything by John Grisham, specifically The Appeal, A Time to Kill, The Chamber
Anything by Khaled Hosseini
The White Boy Shuffle, by Paul Beatty
If you enjoy science fiction, read:
Anything by Isaac Asimov, the Tolkien of Science Fiction
Dune, by Frank Herbert
Ender's Game, by Orson Scott Card
The Uplift War, by David Brin
In other news, shame on Tony LaRussa. Go Pack. Roll Tide. All that.