The Elements of Style

Style is not the only dimension to writing, however, for an aspiring writer, it is just as essential as plot, pacing, setting, and characterization. The good news is: it's not rocket science. One of the best aids is The Elements of Style by Strunk & White. Originally, Strunk wrote the core text in order to teach his English courses, and even though it dates from around World War I, it's been amended--and it is not only easy to follow, but very relevant to modern writing.

Newer writers should, in particular, pay attention to the sections:

• Use the active voice. [as in not in the passive voice]
• Use definite, specific, concrete language.
• Omit needless words.
• Write with nouns and verbs. [as in not with adjectives and adverbs]
• Do not overwrite.
• Do not explain too much.
• Do not construct awkward adverbs.
• Avoid fancy words.
• Be clear.
• Use figures of speech sparingly.
  

Usually I find that I forget the majority of the recommendations, but I think if at least some of it is applied, the writing improves dramatically. And, as with anything, advice can be taken too far, but if taken in context, the recommendations are reasonable.