Although this may seem to be a small matter, types and color of clothing are very important. Try to wear light, even bright and colorful clothes, or something that identifies you with a country or football team etc., and have your non-thumbing hand visible since light colored clothes inspire more trust than darker clothes.
- "Creating trust in Ridesharing Networks"
- Hitchhiking page on the Trust metrics wiki
- The neglected art of hitch hiking: Trust, Risk, and Sustainability, by Graeme Chesters and David Smith
- Understanding and Designing for Perceptions of Trust in Rideshare Programs by Vineeta Chaube