A writer’s primary goal is communicate. Many writers mistakenly believe that complex and inflated language is needed to be a strong writer. Often, clear and simple language is most effective. Writers should avoid masking empty or shallow ideas with language that distorts. [EDIT]
Many inexperienced writers seek to use the most difficult and unusual words they can find, often resorting to the thesaurus and purposefully choosing odd words. The reality about skilled writing is that words must be appropriate and no single guideline exists for what words are best suited for a piece of writing.
Words chosen must fit the content of the writing, must support the appropriate tone for the writing, and must communicate effectively with the intended audience.
One important aspect of language is the level of the formality of the language; another is the connotation of words. Consider the use of these terms: “police officer,” “cop,” and “pig.” While all mean the same thing, each word has a level of formality and a connotation. Most words in the language fit along similar scales. Refer to the following on-line resource as you consider the proper level of your diction: