Difficult spelling words are the bane of students and adults alike. Unless the habits of correct spelling are ingrained early on, the incorrect way of writing difficult spelling words will establish itself as a habit well into adulthood.
Rather than surrender to the seeming inevitability of these spelling traps, it is possible to aggressively address the issue. First, you must identify the most difficult spelling words. Second, you must come up with strategies to turn the correct spellings into permanent habits.
The first task, identifying the words, is done fairly easily with a search on the Internet. YourDictionary.com has listed the 100 Most Common Misspelled Words and included many tips on ways to remember the correct spellings.
Some other sources for learning difficult spelling words are:
While it is certainly possible to try and learn all of these words through rote repetition in the hopes of memorization, it has been shown that there are better strategies. The strategies tend to follow the types of learning that have been discovered through education research, things like kinesthetic, auditory, etc. More information on these subjects can be found in many places on the web, such as The University of Illinois.
Most likely, the most effective learning strategy for any given person is going to need to be individually tailored. A combination of the following techniques, or something completely different, may end up being the mnemonic device that keeps you from ever misspelling "misspelled" again. Find what works, and then use that in combination with drill and repetition to come up with the best strategy.
The most effective way to learn to spell, however, is to simply read. Inspiring reading in children will give them an intuitive grasp of grammar to the point where the words in the spelling tests will simply "feel" right. Parents who take the recommended words for their child's developmental level and turn them into fun games and stories will be adding the most effective ingredient for any kind of learning to their child's education: the ingredient of fun.