Slow growth is more a matter of perception than reality with orchids, but it is so easy to become frustrated when you're watching a plant carefully. Here's an idea to help you deal with the problem.
Once a week or once a month, measure the height of your orchids paying special attention to the new growth. You will be surprised at how fast one of the growths lengthens once it has started growing. It does seem to take a long time for the initial growth to start, but once it starts elongating you'll be surprised at how quickly the growth actually happens. Keep a log for a month or so, or as long as you are interested in the exercise and you'll be surprised at the growth as well as learn quite a bit about how your plant grows.
Especially when watching Cattleyas, you will see the natural development of the growth and the way the leaves unfold. Some of them will have mostly one leaf per pseudobulb, some two, some three, and some a combination -- it all depends on the background of the plant. New flowers will develop in a sheath at the same time as the leaves. Depending again upon the hybrid background, some Cattleyas will develop buds and bloom on the new growth and others will wait until the next flowering period for the buds and flowers to appear. As you watch, you will learn exactly how your particular plant grows and develops so you will know what to expect it to do in the future.
Dendrobiums in particular will really take off once they have started. Once the growth is at the same height as the older growths, start watching for signs of an inflorescence at the top of the plant between the highest leaves. Sometimes multiple inflorescences will appear on the new growth as well as on the old canes. Even canes with no leaves will put out inflorescences so don't cut them back.
A Phal inflorescence will grow quickly once started and develop buds and bloom on the new inflorescence. Stake it as it grows for best presentation and after the growth is about six inches high turn the plant 180 degrees to force the inflorescence to grow in the opposite direction. After that, do not turn the plant again.
While you spend time measuring your plant, check all the leaves for pests and molds. Spray immediately if you see any activity. Take the time to make sure that the new growth is properly staked so that flower presentation will be perfect. Except in the case of Phals, turn plants 180 degrees each week so that the growth will be upright rather than all on one side.