I grew up around hunting big game with basic archery tackle. I was taught a few different techniques during my youth, but the one that I feel helped me the most was shooting for the exit. I found that shooting for the exit better helped me to visualize the center of the vitals within the game animal, and it gave me less room for error than shooting for the entrance. Later on in my life when I taught my children, I used this same technique which works equally well with a centerfire rifle, and in fact becomes much easier being there are fewer limitations with shot presentations. Exposure to real game animals and realistic 3-D targets are better teaching aids than 2-D pictures to help kids visualize the path through the vitals and out the exit. In the end, if you think about it, you are actually aiming at the same unseen spot withing the deer no matter which shot presentation you intend to take.
Good Luck