Socialism's mantra is, "From each according to his ability, to each according to his contribution." Everyone in society receives a share of the production based on how much each has contributed. That motivates them to work long hours if they want to receive more.
Workers receive their share after a percentage has been deducted for the common good. Examples are transportation, defense, and education. Some also define the common good as caring for those who can't directly contribute to production. Examples include the elderly, children, and their caretakers.
Socialism assumes that the basic nature of people is cooperative. That nature hasn't yet emerged in full because capitalism or feudalism has forced people to be competitive. Therefore, a basic tenet of socialism is that the economic system must support this basic human nature for these qualities to emerge.
These factors are valued for their usefulness to people. This includes individual needs and greater social needs. That might include preservation of natural resources, education, or health care. That requires most economic decisions to be made by central planning, as in a command economy.