What I do is turn the target around so that the new shooter is shooting at a big blank piece of paper or cardboard. This way they are not trying to hit the bullseye and being disappointed when they do not. Instead they are rewarded every time they hit the blank target. I find that after many years of training new shooters, this works best for the initial sessions up until we start working on precision shooting.
Also if you can, stapling or taping balloons to the target goes a long way to increasing the fun factor. If it is your own range than steel targets are the best to use.
The worst thing about growing old is that other men no longer see you as dangerous.
Gun resources for senior citizens at The Old Gunhand