First of all, it's not "polite" to type in all caps. Secondly, there isn't a specific format. A Dean's letter is just that. A letter, so should follow the format of a formal letter. It hopefully should say how good a student you are, etc etc etc. They tend to be just general letters because the Dean doesn't really get to know all the students. LOR's are the same. They're formal letters so follow just a format of a letter. They should be from profs/consultants who know you well enough to be able to write you a good letter...how enthusiastic you are, etc etc etc. If you just ask someone, I'm sure they've probably had to do it before so would know how to write one. Just make sure it's from someone who likes you.