In general, the better you can see outside, the less motion sickness. It’s driven heavily by a disconnect between your vestibular sense and visual sense. Your vestibular system needs periodic “updating” to remove the inherent drift in it. If you feel sick, looking outside helps reset that drift, alleviating the symptoms. Many people feel ill and decide to close their eyes, look down, or read to take their mind off it. Bad idea.
Keeping cool (even slightly cold) also helps some people.
Keeping cool (even slightly cold) also helps some people.