The Periodic Table of the Figures of Speech: 40 Ways to Improve Your Writing is a nice resource that helps you use figures of speech in your writing to help you convey your meaning.
It covers metaphors, onomatopoeai, hyperbole, irony, personifications, climax, parenthesis, ellipsis and alliteration. Everything is categorized and organized with descriptions to show you how to use it.
This is a great tool for anyone who writes, including teachers and students.
(the site has some other great resources too)
Related Article about Lifehacker (great resource for everyone for everything)