Today has been one of those days, so I am going to post a few quotes out of the book of advice for writers I have sitting on my desk. Some of these crack me up but are actually good advice :D
Avoid run-on sentences that are hard to read.
No sentence fragments.
It behooves us to avoid archaisms.
Also, avoid awkward or affected alliteration.
Don't use no double negatives.
If I've told you once, I've told you a thousand times, "Resist hyperbole."
Avoid commas, that are not necessary.
Verbs has to agree with their subjects.
Avoid trendy locutions that sound flaky.
Writing carefully, dangling participles should not be used.
Kill all exclamation points!!!
Never use a long word when a diminutive one will do.
Proofread carefully to see if you any words out.
Take a bull by the hand and don't mix metaphors.
Don't verb nouns.
Never, ever use repetitive redundancies.
Last but not least, avoid cliches like the plague.
How to Write Good
~ from William Safire's Fumblerules
When you catch an adjective, kill it. ~ Mark Twain
Make the familiar exotic; the exotic familiar. ~ Bharati Mukherjee
Tell almost the whole story. ~ Anne Sexton
The trick is leaving out everything but the essential. ~ David Memet
And one of my favorites (this actually is exactly what I did in my first book when I had written myself into a corner - and it worked beautifully!)
When the plot flags, bring in a man with a gun. ~ Raymond Chandler
(or as my friend Kristal told me - if you get stuck, shoot someone) :D