Spelling Mistake Research
Many people cannot spell, they make typing mistakes, type too fast and make keyword misspellings or they simply write words in a different way. Color in the US is written as "Colour" in Australia. etc.
You can take advantage of this by targeting the common misspelled keywords. Such keyword typos are often far less competitive.
If we go back to our Sydney Hotel example, lets try and find the different ways people spell the word accommodation. To do this, use the query: spell:accommodation
Note, the different ways in which people misspelled "accommodation".
If you target the common keyword misspellings in your PPC campaigns and even in organic SEO, you can get a real edge over your competition.