I always signal unless traffic requires me to have both hands on the handle bars. Then I do an exaggerated look the direction I'm going to go.

I never use the right hand signals for turning because they are not universal and I live in an area that has a high population turnover and a lot of tourists and transients. In fact, I only ride with one person who uses right hand signals and when we get together and until I get in synch with him I have to think for a second or so to figure out what that casual point with the right hand means.

As for motorists I try to always do the same think on the bike I do in a motor vehicle; make eye contact. A long time ago I learned that a driver can't see you unless you can see the driver's eyes. So, I always do my best to be able to see the other person't eyes, either directly or in a mirror.

I also do my best to thank every driver or cyclist for watching out for me at intersections and other traffic areas.