Over at yourDictionary.com, it has a good reference on the top 100 often misspelled words for English. On top of the word list, it also describes the reason of why it is easy to misspell. Examples such as:
changeable: The verb “change” keeps its [e] here to indicate that the [g] is soft, not hard. (That is also why “judgement” is the correct spelling of this word, no matter what anyone says.)
committed: If you are committed to correct spelling, you will remember that this word doubles its final [t] from “commit” to “committed.”
experience: Don’t experience the same problem many have with “existence” above in this word: -ence!
lightning: Learning how to omit the [e] in this word should lighten the load of English orthography a little bit
occurrence: Remember not only the occurrence of double double consonants in this word, but that the suffix is -ence, not -ance. No reason, just the English language keeping us on our toes.
100 Most Often Misspelled Words – [yourDictionary.com]