Dear boringengineer,
You need to tread carefully here as writing your own recommendation letter, even with the signee telling the admissions office he/she did, is a risk. Writing styles show through and will be noticed. Nevertheless, this is an unfortunate reality faced by many as most people do not want to take the time to write a recommendation letter for someone else.
The most important thing to convey in a recommendation letter is how the person contributed and added value, making the letter stronger by providing examples. So if you were on a successful project or endeavor, that would be good to highlight. Similarly, business schools look for leadership potential and evidence of a managerial skill set in candidates. Thus any anecdotes or examples demonstrating these skills is beneficial.
Good luck,
Lisa
