All excess income over monthly expenses can be first used to decrease your debt. If you are in debt, your interest paid on that debt is not increasing your net worth. Your net worth is only increased when what you own continues to increase versus what you owe; this is just an equation. The less you owe...the more you own and therein you will find more peace of mind and financial stability in your life.
You start by completing the Monthly Spending Plan Summary worksheet and fill in each line as needed. This total allows you to know the number that it takes to live within your means each month. Your net income goal will be to have an average amount of deposits to meet your monthly outflow of cash. In months where you make more income, do not spend the excess, keep it in your account. You will need this excess cash when you have a month where your income is not enough to meet your monthly cash outflow.