[li]if the original word is one syllable: spinner
if the original word has its accent on the last syllable and the accent remains there after the suffix is added: dispelling, occurrences
if the original word is a prefixed word based on a one-syllable word: resetting[/li]
Do not double the final consonant …
[li]if the accent is not on the last syllable or if the accent shifts when the suffix is added: murmured, reference
if the final consonants are x or w: waxing
when adding a suffix that begins with a consonant to word that ends in a consonant: dauntless, equipment[/li]