That is how the old saying goes and it is true - the best time to prune roses is when the forsythia shrubs start to bloom. Here in north Alabama, that usually happens in late February and early March.
We don't have a forsythia in our garden but we planted a few at Michael's salon. As you can see, they are in full bloom.
I grow mostly old roses which do not require the severe pruning that hybrid teas do. One exception are the miniature roses. They are pruned hard. The following photo shows the miniature rose "Sweet Chariot" before pruning...
and after pruning...
Shrub roses do not require as much pruning. Generally, I cut them back about 1/3 and remove any dead canes. Here is the rose "Daydream" that was planted last year -
after pruning -
Cuts are made right above outward facing buds (if you look at the stems of roses, the buds are easy to spot).
Some roses (especially older ones) may be denser in growth and have smaller canes. An example is this "Weeping China Doll" -
Because it has so many canes, pruning by hand can be time consuming. For jobs like this, I just use my hedge trimmers and go back and cut any jagged edges with the hand pruners.
Climbing roses do not require much pruning either with the exception of removing dead canes. Here is a climbing rose that I'm growing on a tripod (not very well I might add). Notice that Isabella always manages to find a snoozing spot within camera range - she's such a ham!
Large shrub roses like this "Buff Beauty" are probably the scariest and most difficult to prune. This rose is centered in the garden and has free range to grow. Unlike most of the other roses in the garden, it is not restricted by other roses and plants. Unfortunately, it got much larger than I expected it too. As a result, it blocks the view of the statue and the wall behind it (I wanted an unrestricted view from the opposite end of the pergola).
I'm afraid to prune this rose back too much because it has such a beautiful cascading shape when it blooms. (The following photo was taken several years ago before the wall was completed)
For now, I'll just remove all the dead canes, which were considerable, and lightly prune the tips of the longer branches. Even though the girth of the rose hampers my design plan, I'd rather have a beautifully shaped rose.
When it comes to roses, don't let pruning scare you. I learned many years ago that not pruning can affect the health of a rose and even lead to its decline.