Guidelines for spelling and hyphenation ensure that writers use consistent spellings for terms within and across works. In general, spelling and hyphenation should match the spellings given in either the Merriam-Webster.com Dictionary or the APA Dictionary of Psychology.
Use the automatic spell-check function of your word-processing program to check for spelling errors. Although spell-check cannot take the place of careful proofreading (because words spelled correctly may be used incorrectly), it will lessen the chances that typographical errors make their way into a published article or a submitted assignment.
Some spelling questions are actually capitalization questions; see the guidance on capitalization for more.