What do you mean by cut your coat according to your cloth and keep within your budget?

It means to brag or boast about ones' self, rather than letting other people say good things about you.

Usually, when people brag or boast they exaggerate their own accomplishments or virtues, to make themselves look good. If I hear a third person say something good about you, I am more likely to believe what they say, than if I hear it from you. An independent reporter is more believable than the person themselves.