Sometimes, you complete a temp assignment but the boss is too busy to write you a reference and they say that you can write it yourself, and they'll sign. Where do you start? The answer is to take what you do, insert adjectives to describe how well you do it, and there you go! And if your boss has given you some feedback (such as "you're just so organised, I really appreciate that"), then integrate that into it. Take time to write it well, and check the spelling and grammar carefully, since you are getting the chance to actually ensure that what goes into your reference letter makes you look as good as possible.