To be a successful manager or supervisor, I've found that the single most important behavior is to Lead by example. For instance, it's unrealistic to expect your workers to put forth maximum effort if they see you being habitually lazy. Keeping in mind that a team is only as effective as it's leadership you can see that a strong or weak manager/supervisor/leader has a HUGE impact on worker performance.
Another technigue that I find useful is to get everyone working towards a common goal (Usually the Companies). That way, with the goals firmly established, the workforce is crystal clear on job performance expectations.
We can observe that there are many kinds of people round the globe. Some of them are pretty confident to become leaders while others just follow what others make them follow. The 1st category is of those who have a couple of abilities to be employed in many fields to express them at their level best.
I was also a group leader during my academics. I was supposed to conduct science lab practical. I was also a member of organizing committee of my department at university. We were supposed to organize picnics, study tours, parties and functions at department level. I supervised welcome party for our juniors with the help of other organizers. I arranged a record party. It was very economical.
You know everybody admired because I came to know that still our forerunners were unable to compete that party. It was an honor for me that I was the head organizer and I did that thing at my level best. It is our determination and capabilities which make our tasks easier than before. Hope now it must be clear to you that how leadership capabilities are there in the people and how they explore it unexpectedly.