This article contains some EXCELLENT advice about how to improve your writing at the sentence level. As you have probably guessed from the way I make comments on your Storybooks, I am a big believer in the sentence level of writing. Not every sentence you write will be fantastic, but if you can get just enough fantastic sentences - maybe one or two in every paragraph - then you will end up with a fantastic piece of writing. Be sure to read the article for all the details:
5 Ways to Write a Damn Good Sentence
by Demian Farnworth
Here are the main strategies that it explores:
1. Insert facts.
2. Create images.
3. Evoke emotion.
4. Make promises.
5. Practice, practice, practice.