One of Socrates' most important contributions to Western thought was his method of inquiry known as the 'Socratic Method'.
The 'Socratic Method' was a series of questions and answers posed until you arrive at the truth or solution to a problem. It was designed primarily to force one to examine their beliefs and the validity of those beliefs.
He also employed this method to examine the prevailing ethics and moral concepts of his day. For this, he has been largely regarded as the father of political and moral philosophy. His method also led to the use of the Scientific Method, as we know it.
Socrates believed that the best way for people to live was to pursue wisdom and self-development rather than material wealth.
He felt that virtue was the most valuable of all possessions and to know the good was to do the good.
He also stated that: "the unexamined life is not worth living" and reinforced the important notion to "know thyself".
Socrates also felt that he knew very little, which was why he was always striving to learn and pursue truth - "One thing only I know, and that is that I know nothing."
Unfortunately for Socrates, the Greek authorities did not appreciate his love of wisdom and his "corrupting" the youth with his unorthodox views.
For his beliefs he was sentenced to death, which he went to nobly (by drinking hemlock) and without regret.