i ride in car lanes, just left of center. it keeps cars from passing you. but i can go about 40mph ... so people don't cut me off like they used to before the upgrades.
i also have no turn signals, so i try to signal if cars are around me. not that it matters much, car drivers are a pretty hasty lot and don't know turn signals. i only really use them for left turns (since an arm extended might mean something to them). for right turns i just go and get the heck out of their way before i get hit.
if you do use hand signals ... i've learned to do them more than once. so give the proper signal ... then wave your hand around in the air a bit ... then point to where you are going a few times. then point to you, then back to the direction you're going. (it tells drivers "hey! over here! see me? i'm going over there!"). then check your mirrors (if you have them), brace yourself, and go for it.