Have separate bank accounts.

One for savings.
One for expenses.
One for emergency.

Take your salary, and the first thing you do is keep your savings portion (10% to 50% - its up to you how much). No matter what happens, do not touch this money at all cost.

Whatever you have balance from that, use for expenses. Write down everything you spend your money on. Once you start doing this, you will know how to control your expenses.

Whatever remaining balance, you keep it in your emergency account. This is your emergency "supply" in case you need spend extra the following month.