• Make eye contact with every driver possible. I believe that even the most ignorant maniac will acknowledge your existence.                    

• No drivers understand the concept of momentum; that it is earned by cyclists through effort. We must have the right to preserve all momentum, but be careful!       
• Personally I observe all traffic lights and so forth as they provide a welcome place for a "breather" (ironic given you'll mainly be inhaling exhaust fumes I know!)
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• I allow about 1m between myself and parked cars as I pass them. It would be a shame to be taken out by an "exploratory" door opening. Also gives anyone who looks before opening their door a better chance to see you coming.
• No driver, if asked when in a rational state of mind, wants to be involved in an accident. It may hamper their search for ever cheaper insurance, or worse scratch their pretty paintwork.

• I find it enjoyable to make an effort to remember licence plate numbers. After all it's not as if we're attempting to pilot a heavy (and fast) metal boxes around, so should have some spare mental capacity!
• (Of course having a camera mounted takes the effort out of this!)