When I say ignore the spooks, I mean as you're riding along and your horse jumps, don't react. If you react to every reaction your horse makes, you make a reactive horse, which translates into a spooking horse.
Say you're riding along the trail, and you come up to a big scary stump that makes your horse stop dead in his tracks. What do you do? I would support him, by letting him feel me in the rein, but otherwise I would stand there and allow him to digest what is causing him to be frightened. By telling the horse to ignore the stump and continue on, you are adding more pressure to the situation which doesn't help his confidence. You relieve the pressure by allowing him to be at the very closest he's comfortable with. Then quietly once you feel he has relaxed some, you encourage the forward again.
When I said pet on him, the petting was to reward the horse for making the decision to move forward without being asked, which also means he was rewarded for his confidence and bravery. That he on his own decided he was okay and proceeded down the trail.
My whole point is that you don't train a horse to be confident and relaxed on the trail if you aren't careful not too add more pressure once it is already present. And by not reacting your horse will find confidence in you because you are calm and confident yourself.
In riding, a horse's energy is like a river- guided by the banks but not stopped by them.