Ensure that your hair is neat or casually styled messy. Don’t overdo the clothing. This person has said yes to dating you because they already likes the way you’re presenting yourself.
Crack some jokes if you’re comfortable doing so. Ensure that they’re genuinely funny and avoid any jokes that require the debasing of others. Be self-deprecating. You could even mention some funny facts about how things were for you when you were crushing on your date and how great it is now that you’re actually dating.