motivation..?

Try giving some reward. Depending on what age group you teach. Stickers work well for the younger kids, but won't do for the older elementary children. Try using candy. I do not suggest candy for young ones though, as they might get too hyper and become a bigger hassle to deal with. Also, they're parents may not appreciate you giving the young kids candy. You could go for something that the students love. for example, if you know they love hockey, try giving them hockey cards for every major achievement

To become an effective tutor, do not limit yourself to the time given to you. You should give extra time to let your pupils learn flute. To those who are left behind with the discussions, you have to teach them person to person. They cannot find interest in playing flute not unless someone motivates them. It takes an elder's motivation for them to understand more the meaning of your teachings. You may also ask about their favorite songs and try learning how to play them in flute. This way, you have let them be engaged in the flute practices. You may also give them special time in front of the classes to play flute to make them feel more appreciated. If ever they fail, you should follow and guide them closely to make them feel not disappointed and discouraged. Children are easily tempted to give up. That's why it always takes some parental guidance to enlighten them. Hope this helps.