The best way to save time is to really organize your schedule. Allot a specific amount of time for each task or activity and make sure to end the task and activity whenever the time is up, even if it may not be done. Then, add time in to finish the next day. This way, you can always incorporate free time into your schedule. Of course, if something is urgent, you should finish it right away, but very few things take this kind of priority.
Your kids come first but you need to come first sometimes as well in order to be the best mom you can be, and that is why organization is extremely important in time management. A happy mom is one that is organized and rested and I think if you try this method, you will be on your way to more time to do things that you don't get to do now.