I would keep it relatively short and sweet. I always like to add something about animals (I have 3 cats and 3 dogs) and also something related to other interests. For instance I might ask if a guy has any tattoos and explain mine... Or I would add something about my job.. I've been a firefighter, EMT, and currently in law enforcement... and I usually would look for a guy within one or more of those... and maybe add some humor from one of those (my favorite one to firefighters is "God made cops so firefighters would have heroes..lol") but that's because a big part of who I am is my sense of humor... so that's not going to work for you.
Just add something about you that makes you special, that makes you, you! But nothing weird like "By the way, I was born with a tail," or "I have 6 toes on each foot" LOL because that might make her run. It's kind of like a resume, you want to make it short and sweet and sell all your best points... but don't write it like a resume, just write it how you talk.... Don't be afraid of using emoticons, especially if you're saying something funny, that way she knows it was a joke and not that you're being serious.