Even I have gotten caught up in making my students look good. I cannot tell you how many players are out there who "look good," but have consistently terrible results. As I have gotten older, I have also changed my approach.
 
My theory is, when I teach a younger player, I have time to patiently teach the proper strokes, etc. The actual winning will come in time. As I deal with older students, I have become more result oriented.
 
I try to take what they have and use that or build a game from there. For example, these are the questions I ask all my students:

1. Can you minimize your unforced errors?
2. Can you keep the ball low or under the net player?
3. Can you lob a player off the net?
4. Can you move the ball not just deep (or over the baseline) but left and right across the side lines?
5. Can you bring a player forward to the net with a dink or drop shop?
6. In doubles, can you keep the ball away from the net player?
7. Can you keep your serve deep into the service box?