During storage, eggs should be turned a minimum of once a day; two or three times per day is much better.
When turning eggs, try to make sure that each egg is turned 45 degrees each way, totalling 90° over the course of a day. Turning the egg during storage ensures the egg's outer membrane does not stick to the shell.
The method you use to turn your eggs is up to you. Some people prefer to turn their eggs manually by hand, whereas some prefer to place their eggs 'pointy side down' in an egg box at an angle, and change the angle of the egg box two or three times a day. However a growing number of people use their egg incubators to turn their eggs before incubation. This can be achieved simply by using removable automatic egg trays, or by placing the eggs in the bottom of a rocking incubator with just the rocking motor on.