To call an attention to your classmate, as a leader, 
1. silence ----> let everyone know that their is something wrong
if silence did'nt work..
2. shout 
3. magparinig(^_^)
4. be strict 
5. get angry

------> kaso baka magkaroon ng maraming kagalit but it's ok your a leader you get their attention. and as a leader you they listen to you.