The FAA has what they call the Dirty Dozen human errors that occur in aircraft maintenance. Here are a couple of online courses on the topic:
https://www.faasafety.gov/files/helpcontent/Courses/DirtyDozen/player.html
https://www.faasafety.gov/gslac/ALC/course_content.aspx?pf=1&preview=true&cID=107