You will do much more galloping between jumps than actual jumping on cross country, often negotiating terrain from rolling hills to steep slopes. Riders *must* know how to use terrain to make the job easiest and most efficient for the horse - taking the least amount of gas out of the tank!
"Through the energy of impulsion mobilized from within himself, the horse is now prepared, in his physique and emotional attentiveness, to respond instantly to the slightest indications to change his tempo, posture, direction or gait." ~ Waldemar Seunig
Always perform the halt and salute in your Dressage test with aplomb. It shows the judge that you have confidence, and it makes for great show photos!
Moving the bit in the horse's mouth to keep him from bracing against it is preventing the symptom without addressing the underlying cause.
In any lateral movement, keep your eyes pointed to the spot that you want your horse to go to.