Applying for a job

When applying for jobs that I want, I always feel very sure about how to go about it. What to say, why I am the best for the job and whatnot. It was tonight when my sister was writing her own open job application at a company she really likes, that I realized some of the most basic flaws people make when writing those letters.

She mainly focused on what she wanted to tell about herself.
She included irrelevant details.
She was vague about what matters most.

Normally you focus on what you would like to tell people, this time, applying for a job, you should realize that it is about the possibility of an invitation for an interview, not about describing yourself the way you would like it. So decide on what would get you the interview, because the resume and accompanying letter is, in the infallible words of Seth Godin, only a possible reason for rejection.  Make sure it is not for you! Set your goals beforehand and do not take to long. People have to read it!