In summary Tatfeef (measuring short and weighing less) includes all those situations when a person is very assertive in demanding his/her own rights, but does not bother about fulfilling the rights of others. Allah Ta'alah has promised great punishment for people who do this, in the Holy Quran.
In a Hadith the Holy Prophet ﷺ said, "A person can not be a Momin (bearer of faith) unless he likes for his brother the same thing that he likes for himself." (Sahih Bukhari, Book of Iman)
When we are dealing unfairly with someone we must stop and think that if someone else was behaving with me the same way how much this would have hurt me, and whether I would have considered this inhumane treatment. If I behave in a similar manner with someone else it will also cause them hurt and anguish in exactly the same way, and therefore, I should not behave with others in this manner.
Adapted from the talk "Milawat aur Naap Taul mein Kami", by Mufti Muhammad Taqi Usmani DB