Atticus is well-respected in Maycomb (despite his unpopular intellectual, political, and social beliefs and his agreement to take on Tom Robinson's case) because of the longstanding reputation of the Finch family in Maycomb. The Finch family is an old and admired family, one of proper breeding and education—unlike, say, the Ewells or the Cunninghams. These elements of social stature are deeply ingrained in Southern culture. While Aunt Alexandra is deeply proud of this fact, it doesn't seem to leave a huge mark on Atticus's behavior.
For that matter, Atticus is also respected simply because he is a good man who treats everyone fairly and with honor. He does not parade around his status, he is attentive to his family, and he has a wise understanding of the dignity of human life. These qualities help many of the people of Maycomb to see beyond his decisions as an attorney.
Atticus is well respected because of his character and the way he treats other people. In every scene that involves Atticus, he remains calm, wise, and strong regardless of what is going on. When the men come at night to lynch Tom, Atticus is there to defend him and he stands up to the group all alone. Atticus does not speak badly about other people and he always tries to see things from their perspective. He teaches Scout and Jem to do this when he talks to them about the Cunnighams, the Ewells, Mrs. Dubose and Tom Robinson. He chooses to defend Tom Robinson even when most everyone disagrees with him. People continue to respect him though for taking a strong stand without being negative toward those who are against him. His integrity and strength win people over even when they might not agree with him.
Atticus did the right thing to defend a colored man even though many didn't think was to be done. He supported tom even when things were at their worse. He is willing to stand in what he believes is right. Even when the people of maycomb were n't up for the job he stepped it up. Even though tom didn't win the case, Atticus still got a standing ovation from the colored folks after the trial because he did what was right.