The first rule of riding a motorcycle is that everyone on the road wants to kill you.
No truer words have been spoken in the forums. I am not sure what it is, I have had people look directly at me when I was on the bike and STILL drift/swerve towards me.
One advantage I found in riding the Harley (or any Cruiser) is that you can get the pipes loud enough that MOST people will hear you if you rack em a couple times. That assumes they are not talking on their cell phone, playing grab-ass with the other teenagers in the car or distracted by changing their radio stations because they think that their life requires a "Soundtrack" and everyone needs to hear it.
The only other thing is WEAR a Helmet! For several reasons, but mostly because it increases your survival rate. I had the internal dilemna of wanting the wind in my face and to look "cool" but then after my first 70 mph trip and my contacts nearly pealing out of my eyes despite wearing sunglasses, I went with the helmet. Besides, it adds an air of mystery. Helmets and Superbikes seem to go together, but I did feel kinda funny being the only guy in the Harley club who wore a REAL DOT approved helmet. Oh well I was about 20 years younger than most of them too.