The problem is simply that they're fresh enough to still maintain all their liquid; as an egg ages, it dries out through the shell and leaves an ever-increasing air pocket between the shell and the internal skin that makes it easier to peel.In the meantime, try doing a quick cold-shock immediately after they're done cooking. Drain the hard-boiled eggs, give them a quick rinse in cold water, then dump them into ice water - you can add some salt to make it even colder. Make sure it's a large enough volume of ice water that your eggs don't bring the temperature up too fast. This cold shock should help the shells separate more easily.
Rather than make your eggs easier to peel after cooking, you can entirely remove the shellsbefore cooking.
Let them age a week or more. I've tried adding vinegar and salt to the water, but it didn't seem to help.