"I believe the road to hell is paved with adverbs." ~ Stephen King, On Writing.
For example, "The book hit the floor loudly," is a sorry excuse of a sentence.
But what if that's what I'm trying to say? one asks.
Then say it better! If you want the reader to know the land is noisy, show them.
For example, "The book clattered to the floor." Better, right? Or this, "Pages fluttered against the wind before the book met the tile with an echoing crack." There are an infinite number of ways to improve the original sentence. It merely takes some effort! I assure you, it's worth the trouble. Once you learn to identify lazy writing, you soon begin avoiding it altogether.
Things to Watch
Repetitive Adverbs: These would fall under the 'duh' category. Confession: I do this all the time, and I want to smack myself for it.
For example, "Megan smiled happily." Well, yeah. How do most people smile, painfully? I realize one can smile and it be in sarcasm or even sadness. Most of the time, however, smiles are a result of joy, so smiling happily is redundant.
A few more examples would include, "Mindy bounced up and down excitedly," or "Todd paced back and forth anxiously." Again, there are times you'll need to clarify these actions to say more than the obvious, but it's rare.
Intensifiers: These are words which, you guessed it, intensify! Extremely, very, truly, honestly, massively, etc are all intensifiers. According to Grammar Girl, you should avoid these at all costs *except* in dialog ... if your characters are surfers. I truly ::wink wink:: love intensifiers, especially in YA. With teens, everything is bigger, stronger, and more intense. In my opinion, I find they work for me -- sparingly, of course -- because most of my characters are teens. I wouldn't recommend intensifiers if you're trying to be professional or in any way serious.
Dialog Diatribe: This is one of the areas my editor calls me out every time. On occasion, I'm justified in using a particular adverb. These typically involve fast-moving scenes or places where there's already a lot going on, and I don't want to weigh it down. More often than not, adverbs attached to a dialog tag are a result of either unclear or lazy writing. Most of the time, the sentence should speak for itself. When you need more oomph, you add action. If all else fails, then and only then, you may use an adverb. But keep in mind, if you can read the dialog, and it's just as strong without the adverb, leave it out.