I asked a few people about this, and the only thing I heard is that it should be double-spaced. I created a header with my name, LSAC Account Number, and social. As far as margins, I've never heard of any conventions - I just used 1 inch all around with no gutter. I think the most important thing is name/LSAC account number, because it will certainly help whoever reviews your application keep track of who you are.