Encourage and praise
We should guide students through encouragement and praise. If the student still can't control his behavior in class, we can consider letting him sit next to the podium, which can better urge him to concentrate. After class, you can provide him with extra tutoring to make him understand the teacher's good intentions.
Rearrange seats
In order to change the bad influence around students, we can rearrange our seats to prevent them from forming a bad momentum. After class, we need to spend more time and energy talking with students one by one, thinking from their perspective, and thus solving their problems one by one.