I find being mindful of what caused the slip up is so important.
Did I get off track with my workouts because I forgot to schedule it in? Than that's what I need to work on. Did I slip up with making a bad food choice? What can I learn from it? Do I need to learn to say "NO!" more often?
Sometimes we have to slow down and see if any changes need to made. Maybe our goals were to unrealistic. So set smaller ones and feel good about those.
And old English proverb:"Often the last key on the ring opens the door." So keep looking for the right key to your success.