There are cases where an explicit implementation modeling activity, performed by trained oo analyst/designers, might be very important. (points : 3) if you intend to generate code directly from the model and if you are doing component based development (cbd) to reuse components.
if you are considered a packaged solution from a software vendor.
if you are re-developing an existing application for security reasons.
if the project is not based on oo principles

i would first let him be aware that a cover letter is official and confidential and it requires a proper formatting so that the employer doesn't have hard time when going through it. he should write it in paragraphs of about two to four sentences and use proper grammar a , spelling and proper punctuation. i will also advice him not to be emotional and not also to use images.then base his attention to the details of the job described and not other things. that is he be specific to the responsibilities and to the employers requirements. on this he should make sure that the letter reflects how good he is for the requirements detailed by the employer

the letter should not be too long nor too short.