1. Make eye contact. No eye contact is creepy. It's best to err on the side of more, rather than less, eye contact, because you probably don't make enough.
2. Pick up the pace. If you're walking slowly, it's going to look like you're trying to prolong the encounter, so go at least at a trot.
3. Hands are threatening, so keep one or both behind your back to prevent spooking her.
4. Smile! You look prettier that way. Two birds with one stone here: if you keep a smile on your face, you'll look less threatening, and you can tell her to smile to inform her that you want her to be happy.
5. Pay her a compliment to put her at ease. Something non-sexual like, "you have beautiful teeth."
6. It will be clear you're not a threat if she knows you've got something else. You could communicate that you're going home to eat by licking your lips. Make some smacking noises too, if it's dark.
7. Clothes conceal threats, so take yours off.

HTH