I wouldn't agree with not looking at the obstacle unless your horse can find distances for you, as you are approaching, focus on the top rail and count your strides to find your distance, this works for me because it ensures me that I will find a distance and I can move from there, the biggest thing that scares me with jumping is not being able to find distances to the larger jumps, so when I do find a distance, I stress less
The cold blood at the obstacle works like everything else! I know some tricks to keep your cool and not stress; The first is that when you arrive in front of your obstacle you have to look straight ahead (do not look at the bar) and then try to concentrate only on your breath and stride to follow your obstacle. The second is simply not to think about the obstacle at least not before being in front, apply yourself in your curves make transitions (a bit like the hunter) like that by focusing on something other than the obstacle in You will manage to keep your cold blood and your horse. The third is done more during the relaxation, do not stress during the relaxation (ie to make a relax in the calm without telling you that you will jump), otherwise you will both lose confidence and Anxiety.
To keep cool, especially at the beginning, try to think as little as possible and do all the exercises required. Once this habit is taken it will be a lot easier !! :)
I hope this helps,