You can think of each individual claim in a patent as being a separate "infringement checklist." For a given claim to be infringed, all the elements of the claim must be present in the accused product or method, either literally or in the form of an "equivalent."
A claim is like an AND statement: If any element in a given claim is missing from the accused product or method (and a substantial "equivalent" of the missing element isn't there either), then that claim isn't infringed.
Note, however, that the several claims of a patent are OR'd together -- you might not infringe claim 1, but you still might infringe claim 15. All the patent owner needs to prove is infringement of a single claim.
(This assumes that the accused infringer doesn't prove that the infringed claims are invalid. In over-simplified terms, if the AND statement of a claim returns TRUE when applied to the prior art, then THAT claim is invalid. [Proving obviousness is a more-complicated analysis.])