How to prepare for the Dictation of Really Difficult Words?

Here are some links to webpages containing a number of Really Difficult Words:

Primary school

http://grammar.yourdictionary.com/spelling-and-word-lists/misspelled.html

http://www.writing.utoronto.ca/advice/style-and-editing/spelling

http://www.engvid.com/english-resource/common-spelling-mistakes-in-english/

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Secondary school

http://wps.ablongman.com/long_faigley_penguinhb_1/7/1976/506096.cw/index.html%20parentloc

http://dictionary.reference.com/help/faq/language/s40.html

http://prowritingtips.com/2008/09/594-words-youre-probably-misspelling/