We all encounter people who need to learn a little humbleness. Nobody likes an arrogant and boasting person, even if they are truly exceptional. Sometimes we are that person ourselves!
One method that I think makes a person humble is regularly cleaning their toilets shared by other family members or friends. In many places/situations, people either hire a cleaner for this job or another family member/friend is given this responsibility in exchange of some other task. However, it is very difficult to clean the toilets and still stay egotistical. Lowering oneself to do this kind of task as a habit eliminates any self-centred and conceited views about oneself.