Over the years I've towed a lot in high winds, typically over the hills from Irun to pamplona.
Clearly you need a well loaded and balanced outfit, but there are a few other tips. Try to keep up with which direction the wind is coming from - this helps you anticipate possible gust effects as you go in and out of "cover". You may also get gusts from the gaps between HGVs on your or the opposite carriageway.
In the winter, trees may be less help and there are not many windsock indicators in this country. In hills the wind direction can change very rapidly as it swirlls round the various bumps and valleys.
If you are mixing with HGVs, try to get as far to the left as you can as they overtake you, and back off a bit, such that the gap between you and them as they pull in gets as big as possible as quickly as possible.
Drop you speed - particularly in anything of a head wind - remember the drag of the outfit goes up as the square of the speed, and 40 mph into a 60mph wind is an airspeed of 100 mph.
It is easy to loose touch with the elements from the comfort of a nice warm dry car. Remember this when you stop and be very careful opening doors, particularly if the wind is from behind you.