Find and Replace:

A useful strategy to help check for known common errors is to use the “find and replace” feature in your word processing software. For example, if you confuse “its” with “it’s”, search for occurrences of each in the document and decide which is appropriate on a case by case basis. The same strategy could be used to search for misuses of “their”, “there” and “they’re”. 

This strategy can also be useful to check for words you tend to overuse.