How can I focus on pleasing Allah Almighty and disregard people's opinions, and what books can help me with that?

The satisfaction of a believing servant lies solely in the satisfaction of his Lord, while a sign of the hypocrites is their eagerness to please people. Among the things that help attain Allah's satisfaction are: the servant's knowledge of his Lord and his certainty that all matters are in His hand, his belief that people's love and satisfaction are by Allah's permission, and that the heart's turning towards people's satisfaction is a failure, and his realization that there is no way to please all people.