I try to be light footed on the motorway, but thats only so I can let rip on the twisties!
Dont be mean to yourself, you have to let go now and again, just take it easy on the motorway and town and fly on the twisties, get a nice balance. Also try not to start/stop too much, momentum is the key to good MPG, and you can have fun in the twisties without burning *too* much fuel