I can instruct but if things go bad and the student doesn't have a clue why their rounds are going somewhere, I'm not sure I have the correct and easy answer.
A good instructor can solve every problem that arises and the student should be able to hit accurately on demand with speed.
Case in point since it happens to me. I align and press. That's all there is to it.
Now the problem. I align, I see the front sight and press. I actually see the front sight in recoil, the front sight settles down and the bullet is off to the side and down. How did that happen if I saw the front sight go up and down?
The reality is I didn't see the front sight go up and then down. I missed the muscle contraction that made me move it to the side and down even if I THOUGHT I saw everything.
If you lie to yourself you did everything right, you're lying to the instructor so he can't help you. A good instructor will see through the lie and explain the muscle contraction as the trigger mechanism went off before the ignition and the recoil.
A good instructor will set you up with a laser so he can see what's happening. A red dot doesn't lie but they are very difficult to learn.
A bad instructor will
Be there for their own ego
Instruct without correction
Discuss self defense and war stories that have nothing to do with accuracy and speed
Have a final test without helping to improve after the test
Excuse their poor students performance on the students
Take credit for a good students performance even if the student came with those skills.
Completely discount the students who drop out as never existing.
Ignoring the highly skilled students without adding to their knowledge or performance.
Ridiculing poor students instead of inspiring them.
A bad instructor won't inspire the student to continue to learn.