I visited a friend several weeks ago, and her ten-year old Judy was double-dipping on some tomato dip on the table. Judy took a piece of bread, dipped it into the dip, chewed a piece off of that bread and dipped again. Mom got upset since the tomato dip was being shared by everyone sitting at the table, including the guests. Mom told her that next time she shouldn't do it. Several minutes later, Judy double-dipped the olive spread that was on the table, too. Once again, mom looked at her and sternly said that 'next time you shouldn't double-dip.' I asked mom at a quiet moment several minutes later if she tends to tell Judy lots of 'next time...' messages, and mom said frustratingly, "Yes, and she just doesn't remember the next time!"
Very possibly, your child is not an auditory learner, and learns best with a kinesthetic/tactile teaching approach.
Perhaps, Judy is careless, or she may have been double-dipping for years such that this behavior is already a habit by now. Perhaps, Judy doesn't appreciate why double-dipping is a problem for some. She might not care if you double-dip and she eats thereafter from the same bowl. Judy might not have the concept of public plate or bowl vs. private/personal plate or bowl.
Whatever the reason, if you find yourself frequently telling your child 'next time do this and next time don't do that...' but the message does not seem to stick, it might be time to change the message. Of course, if you tell your child 'next time...' and your child changes her behaviors, certainly stick to this strategy. It's working! And if your child needs to learn about public and private/personal bowls, or that double-dipping is red and dipping from your own plate is green, certainly teach it using the Red and Green Learning System. Additionally, you can help her understand why her behavior is a problem for some, by drawing pictures with the thoughts and feelings of the other person.
If you have done your part to teach your child why she shouldn't do a given red behavior, yet she doesn't use self-control, what can you do instead of saying 'next time'? In Judy's situation, mom might say "We're gonna' practice right now that you're about to double-dip, and as your hand almost touches the dip, you quickly pull back and say 'I'm not gonna' double-dip. I'll just take some off with a clean spoon.'" Mom tells Judy to continue eating her food and then to practice pretending to almost double-dip. As soon as Judy practices doing the green behavior of using self-control and thinking aloud that she cannot double-dip, mom says "Beautiful using self-control and not double-dipping. You simply put some dip on your plate with a clean spoon."
The reason this technique works: Saying "next time" is an Auditory message. Few children are strong auditory learners. (And if you have told the same message to your child a thousand times but she still didn't get it, she certainly isn't an auditory learner, or she would've learned by now.) However, making her practice the green behavior is a Kinesthetic/Tactile experience, and far more children are kinesthetic/tactile learners."
If Immediate Re-practice isn't sufficient to teach your child to use self-control, you might want to try Positive Practice.