You're not getting any reader through your piece of prose, unless you've got style. And part of style, lies in knowing the rules. Everyone says that, right? 'Cause once you know the rules, then you know which ones to break. That's the beauty of it. So, learn 'em and learn 'em good.
Then your very own styled prose is filled with broken bits of standards along with idiosyncrasies no one else can claim.
Time-Tested Writing Guide:
William Strunk, Jr. and E. B. White. The Elements of Style: http://www.bartleby.com/141/
For Science Writing:
A Field Guide for Science Writers, 2nd Edition. Deborah Blum, Mary Knudson, Robin Marantz Henig, Eds. Oxford and New York: Oxford University Press, 2006.
For Non-Fiction Writing:
John Franklin. Writing For Story: Craft Secrets of Dramatic Non-Fiction. New York: PLUME, 1986.
William Zinsser. On Writing Well: The Classic Guide to Writing Non-Fiction. New York: HarperCollins, 1976.
For Memoir:
Natalie Goldberg. Writing Down the Bones. Boston & London: Shambala, 1986.
For Travel Writing:
L. Peat O'Neil. Travel Writing: See the World. Sell the Story. Cincinatti, OH: Writer's Digest Books, 1996.