One question for horse showing. I am good at getting my diagonals correctly but I always have to look down. Will judges place me lower or not place me at all because I look down to check my diagonal?
The trick is to glance down with just your eyes, not your whole head. If you can, start to learn how to feel it. It does take a bit of practise, but it will be much better for you in the future.
If you're on a calm horse and relatively confined space? Sit at the trot and close your eyes. Practice feeling the shoulders/strides and eventually you will be able to feel it... and not have to look down! ;)
As said above, you should work on feeling your diagonal. However until you get there, judges shouldn't pin you too horribly for looking down. Just glace with your peripheral vision, don't turn your whole head. Even though I've been feeling my diagonals for about 6 years, I still occasionally glance down if I'm not completely sure. So as long as you can get your correct diagonal quickly and smoothly you should do fine. Good luck :)
It's always better to look down to get the correct diagonal then to trot around on the wrong one. As said before, it's better to glance down with just your eyes and not your whole head.