Dendrobium Sonia Earsakul

[Helen]

My dendrobium sonia earsakul hasn't bloomed in 3 years since it was given to me as a birthday gift. (My first orchid). I can't believe I kept it alive this long!
Any help with helping to get this beauty to bloom again would be great. Each spring it ususally puts out a new stem ? (can't remember what you call it), but nothing so far this spring. I've just repotted it out of spaghnum into bark mix with charcoal, etc to see if it does any better.
Any ideas would be helpful...which window, how much humidity, how and when to fertilize, etc.
Thanks
FirstTimer