You should designate an amount of your pretax income to contribute to your retirement savings on a monthly or bi-weekly basis and have it taken out of your paycheck, just like your taxes. It's easiest to save money when you don't have it in your hands; you're effectively taking the decision of whether to save that money out of your control.
Take on the outlook that the money you save for retirement doesn't exist, except for in the future. In other words, stay out of your savings account.