no matter how much you practice or how ethical of a hunter you are, losing wounded game is just something that happens at some point or another to everyone. If you can take a positive out of the situation its that very rarely does it go wasted. Coyotes are a very important to the ecosystem as a whole, so no worries if they end up getting a deer before you do.
If more people would go hunting and learn outdoor skills our country would be a much better place.