The title "Sound and Sense" pretty much summarizes the main topic of the poem. Check out our "Line-by-Line Summary" for lots of examples of how the sound of the poem echoes it's meaning ("sense").
But we sort of tricked you. The real title of the poem is actually An Essay on Criticism, which is a much longer poem addressing many aspects of poetry, including the rules of poetry handed down by the ancients and the rules that seem to come from nature.