Typically, scouts for sporting teams are either ex-professional athletes or ex-college and professional coaches; though there are many people who had little to no coaching or playing experience and still went on to become great scouts.
The reason why most scouts are either ex players or coaches is because of the amount of time those people have spent in and around the sport they scout for. Coaches and professional athletes spend hundreds of hours throughout their careers watching others play and learning to play themselves. This experience is invaluable in the scouting field, though it is not always needed. The best scouts, no matter their professional background experience, are great salesmen that can hook a player into coming into an organization, and are people that are vastly familiar with the skills and talents needed to excel in a given sporting arena.
Increasingly, due to digital media and software advancements, scouts are asked to be good statisticians as well as good observers. Scouts looking for high school athletes to come to their college or university, for example, may not have access to hundreds of hours of player film - as is common in the professional sporting world. Instead, scouts must be able to look at past statistics, data and training documents to determine if a player will be a viable addition to their organization.
Finally, scouts need to be aware of what their organization is in need of and what their organization will be in need of in the future. The best scouts do not just sign up players for what their team will need next season, but also for the years ahead. Some of the most notable sporting scouts in history were able to determine what the goals and needs of their teams would be down the line, and were able to provide the necessary talent to keep their organizations dominant for long periods of time.
Scouts then must be able to gamble and bet on young and professional players, but they can never risk too much or else the future of their team or college could face painful consequences for years to come. This makes athlete scouting a tough, competitive and stressful environment that is only for those men and women who can cope with the responsibility of choosing the best person for their organization at the best time.