I just go pretty smooth, leave it in 'economy' mode. I use kickdown or change on the stick if in quick successions of roundabouts and dual-carriageways (they are 70 limit
and about the only opportunities to overtake in single-lane England!)
Sometimes if I'm tired.. or bored, I just cruise at around 15mph, not on main roads, but the country roads leading to my house... I'm not trying to look like a pimp, just enjoying the time sitting in my MB, looking at the countryside... plus it keeps the mud off the car!