Not realizing that all are making effort to bring improvement in themselves at their own level, we tend to point out people's mistakes only to prove them wrong. It is by proving them wrong that we want to prove ourselves right. This doesn't help others in anyway to bring a change in them.
We need to focus more on the potential and unique specialities of those around us, rather than on their faults. This will help us to appreciate the effort that each one is making to bring improvement in himself. Then we find that even the corrections we give are effective, as they are more for the benefit of the other person.
This is the real help we can give to others.