1. Ask them why they're renting. If I'm not happy with their answer, I decline. 2. I look at their verified information. People don't usually give lots of details here, but it does help me establish a gut feeling. 3. I give them thorough details about the area and room, and gauge their response.

It's helped me keep my 2BR/2BA apartment booked solid for the last 8 months with wonderful guests, some of whom I happily consider friends. It also helped me reduce my effective rent payment to levels below most places in the US and Canada, let alone Palo Alto.