I put tires with reflective sidewalls on both my bikes. Not only do they seem to really catch whatever light is available and send it back, but the fact that they outline the tires also signals "bike" to whomever is on the side of me. Whatever else you do, they can't hurt.

Sorry, I don't remember what make, etc., the tires are, I just told the LBS what I wanted (reflection, wider than what I had on at the time, and good all-round commuter) and they sold me tires I like.