Just save a parentage of every money that you earn just put it on the side, this way you will be able to save money.
It is just like holding on to Bitcoin hold on to your money and not spend it.
But what if someone earn some amount of money and his expenditures are much higher that he will unable to save some money from them, that is what the OP want to ask I think, the better answer is that try to adopt some extra work like part time job and save from there