Hello Amber,
Definitely make a video! Just a minute-or-less video which shows you speaking English and/or signing.
Another thing is to just be helpful on the site - people notice and appreciate it. No need to self-promote (that actually puts people off); just answer questions, correct notebook entries or discuss a topic, and potential students will see that you are helpful and approachable. (This is how I picked my teachers here.) You don't need to burn yourself out. Just be visible and active.
One more thing - mention which US state or city you are in. Promote the fact that you are really truly from the USA. Students often pick a teacher because they plan to move to that region to study or work, so presenting yourself as someone with "on the ground" knowledge makes you even more appealing.
Good luck!