Aside from the brightest lights possible, I ride further right, keep alert, and watch the mirror.

Normally, riding left is the way to go. However, in fog, even the brightest lights aren't visible from that far back, particularly if it's not dark out. Moreover, drivers who can't see what they're doing tend to hug the line at the edge of the road. Not only does this move them noticeably towards the right, but they're not looking far ahead.