Pruning roses is easy, however, old rose bushes bloom from wood that has been over-wintered and should only be trimmed conservatively. Heavy trimming of old rose bushes can actually inhibit blooming.
Use a good pair of pruning shears to make slanting cuts above outward facing buds, in the direction of the bud, leaving a maximum of 1/4-inch stub. Do not trim back more than 1/3 of the total bush. This will encourage new growth.
Remove all weak or dead canes in early spring, when growth buds begin to swell. Also remove thin, spindly shoots, branches that cross the center of the plant, or rub against larger canes. Try to retain the natural shape of the bush. Annually blooming roses should be trimmed after blooming in the spring, because these roses produce blooms from wood that has been hardened over winter. Keep some older canes on climbing roses and trim back side growth (lateral shoots). Train the main canes horizontally, for upward growth.
Remove any suckers completely by digging down to where they sprout from the understock and pull them off with a downward motion to remove growth buds that would become suckers in the future. Allow wound to dry in open air before replacing soil.
Berkley Horticulture Nursery recommends that you also remove the leaves from remaining canes as you go into winter to help prevent disease and encourage deeper dormancy in areas that have mild winters.