i believe the key to rooting a plant cutting in water is to keep it warm, but not sunburnt in strong full sun. my african violets all seem to root better in water than perlite or soil! the water level is determined by how the mother plant takes water--roses can take lots of water, so root in 3-5" of water. succulents dont like to stand in water, so root in 1/8" of water standing with only the base touching the water.
There will be disappointments along the way, when many rose seeds fail to germinate, or perhaps they do germinate, only to die several weeks later from damp-off disease. Sometimes a rose seedling will turn out to be as ugly as sin, or very sickly, and you will reluctantly have to throw it away. Other times they will be just ho-hum, or look too much like its parent, and therefore have no value. But, just when you don't expect it, you might discover that one of your rose seedlings turns out to be very special.