November / December is a good time to prune climbing roses before any bad winter weather, although they can be pruned anytime between now and February.
Remove any weak or dying shoots, or any that may be growing in the wrong direction.
If the rose is on a wall, train the stems into a fan shape. Horizontal stems will encourage more flowers right along the stem rather than just the ends.
Prune the side shoots from the main stems back to three or four healthy buds and cut just above a bud that points in the direction you want a new stem to grow.
Rambling roses are treated differently to climbing roses and are best pruned in the summer after flowering.