Shooting on your phone generally means that you’ll be shooting handheld and unless you want to channel Blair Witch Project vibes, you’ll want to keep as steady a hand as possible. Here are some tips and tricks to make sure your shots are nice and smooth:
Use both hands
Keep your hands close to your body, can you feel the difference when holding it close versus far away?
Stabilize yourself by propping your elbows on a table or other stable surface
When filming yourself, position your hand so that it will be easy to press stop before you start filming. That way you can avoid any unnecessary shakiness
Whenever you film, consider if you want the shots to feel handheld. It can be very effective when used properly.