This is a great question. Bernard did several things to address the problems of his time. Let me name three of them.
First, as a christian, he wanted to help the church. What he did was become the primary voice of the Cictercian order. By the end of his life there were over 300 monasteries. So, he was an organizational builder.
Second, he also wrote prolifically. For example, when it came to the crusades, which were going on during this life time. He helped the Knight Templar to build a theological worldview to defend the holy land. In fact, the writing of Bernard in this area became a code for Christian nobility.
Third, Bernard also worked through councils of the church. For instance, when there was a schism, he worked through the church. When there was "false teachings," he fought them through the church. We can see this in his interaction with Peter Abelard.