Make definite
assertions. Avoid
tame,
colorless, hesitating, non-committal
language.--
William Strunk Jr.
Jeez, first published in 1918 by Ithaca, N.Y. publisher W.P. Humphrey, it's full of fun sexist language and other fine things. I do know the person responsible for revising and putting out the Third Edition, but that's not out yet and under copyright. Of course, this text is no replacement for a true usage dictionary and grammar handbook, yet it'll do.
Noded here for your pleasure:
Elements of Style Introduction
Elementary Rules of Usage
Elementary Principles of Composition
A Few Matters of Form
Words and Expressions Commonly Misused
Commonly Misspelled Words (the original is Words Commonly Misspelled, but I changed this for better integration)