Lie. This can lead to instant dismissal if subsequently discovered. Employers do sometimes carry out an auditing exercise when this can be unearthed. It may also be a criminal offence.
Joke. Not everyone will share your sense of humour.
Attach a photograph to your CV as it can give rise to false impressions. Do you really want to be judged on your appearance and not your ability?
Bind your CV. This is inconvenient as it may be copied to a number of departments and/or scanned to a PC. It also gives the impression of trying too hard.
Leave unexplained gaps in your career history. State whether travelling, unemployed, taking a career break, etc.
Write your whole life story. Positions of responsibility at school (particularly junior/prep!) are rarely of interest unless, of course, you are seeking a post immediately subsequent to leaving school.
Write bland profile sections and use worthless adjectives. Statements such as ‘a highly motivated team player with excellent communications skills’ are redundant: demonstrate by example in your CV instead.
List your interests unless they are current. Think carefully about the impression these may leave with the reader. Very solitary interests may raise the questions about your ability to integrate and not everyone will share religious/moral/social concerns. Only state those interests you can talk fluently about.