Deadheading roses involves lopping the head off a rose that has finished blooming. This limits the amount of energy the plant diverts into the flower and encourages it to bud more.

Prune just above the leaf nodes that are likely to grow back facing the direction you want.

Generally, you prune the inward-facing growth, leaving the outward-facing growth, as inward-facing flowers will look crowded and clumsy. It can also obstruct the airflow amongst the foliage, leaving the plant susceptible to fungus and disease.