How would you handle a child who was misbehaving and not following instructions?

I do not work with kids so this is out of my field 

It depends on certain factors like if the child has medical problems which makes him hyperactive. It also depends on the age of the child.  You would handle a younger child differently from an older child. If all other factors are cancelled out, I would firstly warn the child and explain to him why should not behave like that.  If it still does'nt help, I would let him sit detention after school and as a last resort I would contact the parents.

Normally children have very low maturity level for what their act is what is refered to as "childish" behaviour.As an adult, it wouldn't be wise to discipline them by yelling or any actions to vent your anger on them.Instead,be pro active and engage them.Now,keep in mind,being an adult,one should be Patient.One should be patient,listen to the child,engage them and be rational.

u and your child need to be on the same team. You are both trying to get him to the same place, the place of making thoughtful, good choices for himself. And the very first chance you get, catch him doing the right thing. Praise works better than punishment ... and a whole lot better than spanking.

Be advised to abide by the instructions and to improve the behavior so as not to be punished