I've found mounted phals thrive much better than they would in a pot, but that could just be me. As for extra care, water daily, fertilize about as regularly. I prefer to mount my phals with their leaves pointed down (basically upside down). This is (I've read) the way they grow naturally, so they tend to prosper mounted this way. I've actually been considering unpotting all of my phals & tossing them on mounts, just because of how much better they seem to do. Depending upon your growing conditions & area, you might need to water a mount more than once per day.
Here's a few pics of my phal mounts. You'll notice the gigantic new roots growing from one of them - that plant was in bad shape prior to me mounting it.
hope i was any help whatsoever.