There are many techniques to let students think/work by themselves.
Try, at the beginning, the followings :
Method A
Divide students into groups, maxmum eight students a group. Let groups solve a problem.
Method B
To an answer of a student, let other students react. Circulate their reactions. In this stage, your role is just to control their actions. And in the final, you evaluate all of their achievement.
To practice this, you must train children some manners. At beginning, train children to become used to the followings :
After he/she expresses something, he/she asks others "Am I right? How do you think?"
When someone expresses something and he/she bears an opinion about it, then he/she shows by raising his/her hand that he/she has an opinion.
Method C
So far as space permits, place students' seats in such an arrangement that students feel free to discuss among them.