The best way to avoid the Highland midge is only to go out when it is cold and windy. This gives surefire protection and is a situation not infrequently encountered in Scotland.

Midges don't like much of a breeze - they prefer it still and damp. And they don't like bright light either. Wear pale clothing rather than dark as well. There are a number of repellents on the market, plus a crop of rumours - including one that Marmite keeps midges away. (Apparently, it's the yeast.) Those delightful people at Natural Beauty Scotland stock an organic safe repellent which feedback suggests is pretty good. Finally, one way of keeping the midge population down is to encourage bats. Apparently, the pipistrelle bat eats 3000 midges per night. We should all put up bat boxes!