I'm the captain of my line, and I'm also a sophomore.
Needless to say several people have issues with that.
Our line, though, doesn't have a drum tech or knowledgable BD, so the only way I'm able to keep some order is by being the perpetual bad guy...constantly being a strict jerk. This doesn't get hardly anything done and everything has escalated to the point where no one listens to anything I suggest even when it's basic stuff like posture, technique, and not talking during the middle of a warm-up. I need guidance.

Thanks in advance, everyone.

Well
What i found (being a strict student leader myself) is that when i tend not to be a ''jerk'' outside of practice my peers know that Im not a bad guy and respect the fact that Im trying to get things done during practice. In your case if they dont listen just confront them (in front of the whole line) and assert yourself, but be dont come out as an butthole. Remind them that during rehearsal and such its business time.

Remember your the Captain.

Regardless of the position you hold on the drumline, you're expected in any human to human dynamic to be respectful. I suspect that you might be the cause of your own frustration as you labeled yourself as "constantly being a strict jerk."

I think anyone who has experienced your (difficult and unfair) position will affirm that they had the idiot or two that wouldn't follow directions, for to be at the point where "no one listens to anything" you suggest, that would point, perhaps, to a flaw in your leadership. Hopefully you take no offense to my diagnosis.

In my experience being a friend outside of rehearsal was very important and being able to separate business and play as well.

The main priority for a student leader is really to have the ability to be firm and take command while showing respect at all costs to those who you lead. For me, the mark of a good leader has always been for people to enjoy following him.

Would you mind sharing some of your leadership habits as objectively as possible? Maybe we could help you on how to modify them to help become a better leader.

What's your approach when someone is insubordinate, or doesn't know their parts?

Here's my thoughts on this.....It's high school marching band, it's high school marching band...

In respect to all three replies:

The line between in and out of practice is in total obscurity, meaning that our line doesn't recognize that practice is serious business. Inversely, my attempts to be friendly outside of practice are not well-received because they perceive that I am always in Captain mode thus it is me being fake. Disruption primarily occurs amongst my upperclassmen, therefore no one questions their behavior and my attempts to rectify it are met with contempt.
I've been very respectful to everyone on the line, and I believe I misspoke when I said I was a jerk; what I meant is that they perceive me as a jerk because they aren't used to the discipline that goes into a quality line. When leading, I always be sure to make sure that the first priority is getting the job done. This, along with my impatience, is undoubtedly a source of my own frustration. However, when a member is struggling with a piece of music, technique, etc. I allow them ample time to develop the skill without hovering (no one wants the "jerk" helping them). Insubordination, as I mentioned before, is dealt with to a very small degree because of my lack of social leverage over my upperclassmen coupled with a lax sense of discipline throughout the band.
I understand that this is high school marching band, but I have an uncompromising attitude towards the activity and constantly strive for a higher level for myself and the group.
After some thought, I've decided that discipline is not my responsibility and for the time being I have no sway over it. That being said, I've asked my BD to supervise our next practice in order to introduce the air of formality that the line DOES respond to; even if he can't teach everything he can still keep people straight. I still continue to be nice and respectful to everyone out outside the band environment.

High school marching band or not, its still a serious thing.

I understand the "extra challenge" that goes along with leading people that are older than you, and sometimes even people that are your own age. Luckily, in my line, I only have one jerk-bag senior snare who thinks he's all that. The other senior, who is a bass drummer, is awesome and does a lot of work with the basses.

It's good to see that you're getting your BD involved. Since he will be staying with you during rehearsal, I would recommend maybe talking to him about your issue. Don't make it come across at all like you're stressed or frustrated; show him all of your concern for making the line better. Then maybe he could help you figure out something that would help you out.

This

It's not a serious thing people, it's high school marching band. Short of one person snapping and going on a 5 state shooting spree, how is this serious?

This is why I never had section leaders. One high school student should not be put in charge of another high school student. Neither of them lack the maturity to handle it yet. My last couple of years when I did have a section leader, it was always an upperclassmen and everyone knew it was more of an honorary title and their main job was to tap-off everything.

Lemme guess, you were made section leader because you have the best hands, correct? If so, that is the worst way to decide a section leader. Chops have no direct relation to leadership skills.

It sucks that people won't listen to you, but as others have said, you must show respect to gain respect. You're back peddling on how you lead once you got called out for it so the truth is now blurry. With that being said, have you tried to find out why they don't listen to you?

Every group that I taught, I got way more accomplished by staying on point. Someone ticked, cut the run, call out the mistake, how to fix it and go again. Don't call out the individual. Calling out the individual only embarrasses that person. I was notorious for making jokes during rehearsal to keep everyone on their toes. My rehearsals were kept light as much as possible to keep people relaxed and tension free.

Hell, I made fun of the trophies we could win as they are just stupid pieces of plastic.

My point is that high school marching band does not need to be taken as seriously as you guys seem to think it should be taken. Do you want to put a good product on the field absolutely. Do you have to be captain strict to make that happen, absolutely not. Is this a life and death situation...HELL NO!!! It's high school marching band.

Thank you everyone for your advice. Bill, you present some very good points but I'll have to agree to disagree with you on the actual seriousness of the activity as your years of experience have undoubtedly affected a different personal viewpoint. I have talked to my director about practice procedure and he said he would be happy to help. Again, I'm very gracious for everyone's input; it has helped me a lot.