T. S. Eliot's most sustained and comprehensive statement of his own theories of literary criticism can be found in The Sacred Wood: Essays on Poetry and Criticism (1920). In this work, Eliot essentially articulates several positions that can loosely be regarded as anti-Romanticism: worthwhile poetry must be based on historical continuity and common cultural expectations as opposed to idiosyncratic self-expression; intellectual rigor; and empiric criticism instead of emotional criticism.
His best-known and most widely-read essay on criticism, which appears in The Sacred Wood, is "Tradition and the Individual Talent" (1919), in which Eliot discusses the underpinnings of his critical theories, the most important component of which is that the poet must place himself squarely in the middle of historical tradition because each work builds upon the previous body of works and is therefore not to be considered separate from earlier works. It's as if, in Eliot's view, there is a continuous, unbroken line of meaning that the most recent poet taps into and then becomes part of.
In addition, the poet, rather than expressing a subjective point of view--that of an individual looking anew at a situation--must articulate the view of his culture, his age, and express the belief system of his time and society. As an example of this point, Eliot said that the poet is not supposed to "find new emotions, but to use the ordinary ones. . . ." He coined perhaps his most famous critical phrase here when he characterized the poet's goal as "emotion recollected in tranquility," and he said it was neither emotion or recollection or tranquility but "a new thing resulting from concentration," by which he meant a concentration of experiences that unite to form a different, but completely recognizable, experience.