Resumes and cover letters need perfect grammar. Here are selected rules contributed by several experts including Laura A. DeCarlo and Dr. David F. Noble.

• Laura DeCarlo's Competitive Edge Grammar Rules
  
  
• Dr. David F. Noble's Errors and Stylistic Weaknesses in Cover Letters
  
  

Than vs. Then

Than: Appropriate when making a comparison.
e.g., "When comparing one thing with another you may find that one is more appealing than another."

Then: Refers to time and progression.
e.g., "First you separate the eggs; then you beat the whites."