At the risk of sounding like a wanker, once I realised that I should run my harnesses tight, light, REALY tight, I reckon my driving improved massively. It's like you're completely part of the car, no moving around at all.
It's also not remotely uncomfortable, its funny, but once you're moving you don't even notice how tight you are in the car.
Better in case of a big acco too I'd like to think.