How do I become a more appealing owner/renter?

The idea is that you are going to create a trust relation with the person you're having the rental deal with. Of course you meet each other in person but the authenticity of your Gearbooker profile can be additionally confirmed by filling it as much as possible (e.g. use a real photo of yourself (in which your face is visible) and fill out a short biography about yourself) and link it with your social media profiles and your phone number.