Some things I've noted and try to do when driving to improve mpg:
1) When using cruise control on the motorway (That's Freeway in US English!) I go about 5mph past the speed I want to cruise at and then activate cruise control. Observe the real time mpg on the MID and if it decreases then I would knock the Cruise speed down 1mph and this will restore "hypermiling"mode.
2) When coming to sections of road that are slightly uphill you can counter the big increase in fuel consumption by speeding up earlier and Coasting up the hill. This works best for commuting journey's where you get to know the good spots and bad spots for fuel economy.
3) don't use the heated seats if you have them
4) knock off the AC in the mornings. If your screen is misting up give a quick blast of the dedicated front window demist button for a few seconds and that should clear it for a while.
5) dont drive with the windows down. this really increases drag.
6) make sure your tyres are at least inflated to the recommended level. some folks here have pumped them up even more and have received increases in mpg.
7) Get used to the subtle changes you can feel when the IS2 switches from charging to petrol only, to electric only to both electric & fuel modes. Make the most of every opportunity to use electric only (i.e. steady flow of traffic around 20 to 30mph.

Get a feel for how your IS2 behaves with autostop. In my stop go commute if the autostop is not working initially because of any one of a number of reasons, I move off the main road to a "rat-run" route so that the car can heat up and shake of its morning problems. This isn't any quicker but it does seem to give the auto stop a kick up the ass and starts it working. Start/Stop working is the difference between a 45 to 50mpg commute and a 60mpg commute (for me anyway)
I'm open to any suggestions others may have in this area. There is nothing more satisfying than making your way through a gas guzzling commute and still hitting that 60mpg marker! Well almost nothing.