With fuel prices becoming so low of date, maybe discussions about MPG has become a little less topical... however I came across the technique of Hypermiling and have been giving it a go over the last week.
My average commute of 43 miles, mainly against the traffic on M25 from J17-23 and A1M to J9 has gone up from about 47ish to 51ish in a manual GTD.
I think Pulse and Glide, or Burn and Coast provides the biggest improvement.
I’m no engineer but I believe that these engines are more efficient under load than they are just maintaining a given speed. Therefore where possible and conditions permit (without bothering others) accelerate to just over 70 and then coast to about 60 in 6th then potentially change down and boost again for a few seconds, and repeat. You coast furthest in a high gear above 1000rpm, and obviously all this coasting in gear above tick over revs is free.
Also try to time as much of the costing to uphill sections and mainting the boost for downhills, just as you would if you were on a push bike.
See
http://www.hypermiler.co.uk/hypermiling/hypermiling-techniquesand here
http://en.wikipedia.org/wiki/Energy-efficient_driving#Pulse_and_GlideThis could all be complete rubbish, but it appears to work for me – be happy to hear any others experience or comments.