Don't make excuses- to yourself or your family. I know this one from experience. We then spent the next year paying that debt off before we could buy our first home. Expect some resistance to change-from others in your life, especially benefactors of your past spending habits. Setting a good example and having a good attitude are subtle but powerful ways to retrain those spendaholic spouses, children and friends.
Actions do speak louder than words.
Don't get discouraged by the pooh-poohing of these people either. Change is not easy and takes time. If credit cards are a problem for you, cut them up or freeze them in a big block of ice. Track your spending- with a small notebook. Write down everything you spend for 3 months, from the groceries for the month to the candy bar from the vending machine.