Snip off any spent blooms below the flower, 1/4 inch above the leaves on the flower's stem.
Snip off any seed pods that are forming, again cutting just above the leaves on the pod's stem.
Separate long stems from the rest of the pansies. Snip them 1/4 inch above a set of leaves at the desired height for all the plants.
Snip back all stems that have been allowed to become scraggly. Reduce stem height to four inches, always cutting 1/4 inch above a set of leaves.