You're right about cutting off the flower spikes- I'd go ahead and do that so the plant can put it's energy into rooting.
Fertilize "weakly, weekly" is the general rule around here.
You might see if you can find some SuperThrive, it's great to add to fertilizer. (I recently found some cheap($10) at Home Depot.)
The media you plant an orchid in generally depends on the roots, the thicker the roots, the larger the media, and vice versa.
I've had success with my Phals in half bark half loosely packed sphag, with some packing peanuts (green or white) in a single layer on the bottom.
To tell when they need watering- get some bamboo skewers that you can stick gently into the pot, all the way to the bottom. If it's damp all the way down, don't water. Let them dry out a little between waterings (like upper 2/3rds dry).