Some of us are just not good spellers, but that is no excuse for sending out a business letter or resume containing spelling errors.  A research paper or essay with misspellings can result in a lower grade, and an author's misspellings may make him or her appear less professional. 

  Using a spell checker program is helpful, but this type of program will not catch a misspelled word that is not in its dictionary, nor will it highlight homophones, or words that sound similar but are spelled differently and have different meanings.  Common homophones are:

affect, a verb meaning "to exert an influence" 
and
effect, a verb meaning "to accomplish" or a noun meaning "result".

People also often confuse:

their, a possessive pronoun meaning "belonging to them"
there, an adverb meaning "that place"
and
they're, a contraction for "they are".

  Because spell checker programs have their limitations, you will always need to proofread your work yourself, and refer to a good dictionary when you are unsure of a word's spelling.  The Random House College Dictionary, Merriam-Webster's Collegiate Dictionary, and Webster's New World Dictionary of the American Language,  are just three of the excellent dictionaries available.

Remember, when proofreading your own work for spelling errors:

• Don't rely on spell-check programs.
• Examine each word carefully.  Placing a ruler or pencil beneath each line as you read can help you to see each word.
• Consult the dictionary for homophones, those easily confused words.
• Pay particular attention to commonly misspelled words, such as