As important as it is to have a tailored and well structured CV that accurately markets your skills and experience, it is also vital to personalise the covering letter to the requirements of the position description. You can imagine just how many applications come through to employers and how many applicants send through just their resume with no covering letter. And if they do send through a covering, three common mistakes occur:
Writing too much about themselves and not enough about what they have to offer the employer.
Writing too little and coming across that they are not that interested in the position.
Writing a covering letter that is completely irrelevant to the position advertised.
So if on the job advert for example, they are asking for someone who has thorough knowledge of Government training programs, then it would be wise to write about your knowledge and experience on that, but keep it to a couple sentences, obviously taking into account the number of criteria.