This worked with my oldest daughter. I was constantly reminding her to turn in her practice sheets, and running them to school when she forgot. And she kept forgetting her assignments in other classes as well. One day, I realized what I was doing. My child was not learning because she never had to experience her own consequences. So I quit reminding and told her my plan to not rescue her anymore. That semester she got an "F" in Orchestra (this was Junior high). That grade shocked her so much that for the rest of her school career she worked extremely hard to make sure it never happened again.
Another example of not rescuing is letting your children get detention when they are late for school and to quit sending in excuses for their tardies. Of course they won't be happy about it, but they will learn. And you can show an increase of love to them each time they make a mistake. Talk to them about what they are learning and why you aren't rescuing them: because you LOVE them. Tell them you are helping them learn to be successful in the real world.
Now there are some children who don't care about natural consequences such as grades (sometimes this is because of problems in the home and that they are acting out their anger/insecurities, or sometimes they just aren't motivated by those things). When this happens, I think it is important to give them the extra incentive to do better by linking their privileges to their responsibilities, as I talked about in the previous post.
However, remember through all these things that LOVE is the main motivator for good actions. And that if children aren't getting enough love and stability at home, then they will act out no matter what consequences they experience. So make sure you are doing those love languages.
It's important to let your children make mistakes and to let them fix them themselves, even when they are young. They will really learn to be independent and happy this way, and you will be happier too.