It is a little confusing to speak in terms of components of "protect" and "serve" given the fact that the phrase "to protect and to serve" is a motto that originated with the Los Angeles Police Department during the 1950s, specifically, by the department's academy. In 1963, "To Protect and To Serve" was officially made the department's motto by the Los Angeles City Council, which mandated that it appear on all department patrol cars. It has since spread to police departments across the country.
That being said, the essence of the phrase "to protect and to serve" was articulated well by a U.S. law enforcement officer serving in Iraq for the purpose of training that country's police officers in the proper ways of serving in a civil society. For decades, the Iraqi police were an extension of Saddam Hussein's apparatus of repression. Iraqi police officers had no concept of how to police in a democratic society. As that U.S. advisor put it, "We need to instill the moral, ethical and professional characteristics of a police department."
The phrase or motto "to protect and to serve" is intended to remind police officers of their sworn duties, a daunting challenge in a major department. Many patrol officers spend 20-year careers encountering the worst of mankind on a daily basis, with 40-plus hours a week spent patrolling the most dangerous neighborhoods in the city. After so many years, it is not unusual for a certain callousness to creep into both individual officers and departments. Morale suffers, and the public service attitude that inspired most individuals to become police officers in the first place is replaced by a growing disregard for the notion of protecting and serving the public. The result is often corruption, improper discharge of a firearm, extortion, and mistreatment of suspects.
Most major police departments have Internal Affairs divisions that exist to police the police. Because of the possibility of officers becoming corrupt, or of abusing their authority in other ways, they are monitored by their fellow officers who are assigned to Internal Affairs. The psychological toll on police officers serving in major cities is enormous, with depression, alcoholism, and divorce a constant threat to the individual officer's ability to perform his job, which does not pay particularly well on top of everything else.
To extent, then, that one can list components of the phrase "to protect and to serve," they would probably include training for the rigors of the job, periodic psychological evaluations of officers in particulary stressful units, for example, narcotics, and frequent refresher courses in the concept of community policing. These individuals are expected to sacrifice their lives for those of the citizens they are poorly paid to protect. When subjected to the harsh conditions of many inner-cities, that concept can degrade quickly.