Great Question! For the most part Phalaenopsis orchids do not "need" pruning per se.
When the flower spike has finished blooming and lost all its blossoms it is possible to cut the spent flower spike off the plant.
Actually, you have two choices if the spike still is green and alive.
You can either cut the spike (use a new single edged razor blade) about 1/2 inch (a centimenter or so) above where the spike attaches to the center of the plant. Be careful not to cut yourself with the razor blade.
Or if the old spike is still green and alive you can cut the spike the same distance from a node (little bump on the spike where the flower was). Sometimes Phals. will send out another shoot from this node. Usually that means it will bloom just a month or so sooner than if it put up a new spike.
I do this second method sometimes. Not always. I think it is a little harder on the plant so I only do it on really healthy plants and I would not do it year after year.
As to "pruning" the leaves? Phals. do not need that generally. Sometimes the older leaves (bottom ones) will die off. They will either fall off naturally or you can help the process by cutting or pulling the leave. There is a natural attachment place to the crown where the leaf will generally separate easily.
