I hate selecting "captain" or having the seniors be the "captains". What if you have a terrible senior class? Do you really want that group in charge of leading players? I don't like captains because 99% of the time they turn into do as I say people who boss around everyone. "Hey you go pick that up" or "Hey you're a freshman so you do what I say" I can't stand that.
I do like what ironhorse is doing with his leadership council but I'm a big believer in if you establish the program correctly then you don't have to worry about having a captain. I tell my guys all the time......
1. You're either doing the right thing or you're doing the wrong thing - why choose to do wrong?
2. You're either working hard or you're not working hard - why choose to not work hard?
3. You're either hustling or you're not hustling - why choose to not hustle?
4. You're either a head case or you're not a head case - why choose to be a head case?
You can have the list include whatever you want but you're establishing expectations of how to act and perform. When they get "IT" then peer pressure does your leading for you. Nobody wants to be "that guy" who does their own thing. If you get someone who does their own thing now you work to change that or get rid of them since they're a cancer. When you're part of a team everyone is equal in terms of importance because those seniors who are having their last run may need that talented freshmen to come through in the clutch to win. You can't do that if there is a hierarchy just to have a hierarchy.
If you want to have captains the first thing you need to figure out is what do you want the captains to do? Second thing is how do you want them to get that accomplished? It's easy to say you want leadership but rarely does anyone ever teach them how to be leaders. Next thing you know you got a bunch of jerks running the team.