If you state actual problems or questions it may be easier...

One thing you can do long distance is decide what she wears from day to day, decide when or how she contacts you, and so on. You can also control her toilet use, food, orgasms and so on. For example, if you allow her a vanilla lover, you can control if she is allowed an orgasm with him/her or not. If she is alone, you can state that she is only allowed to orgasm when she is given permission (and you say how she is to cum as well) and possibly only when online/on the phone to you

A lot of online stuff that works best are writing tasks so maybe get her to keep a journal of her fantasies? You can also get her to perform tasks for you and send you video, photo or audio evidence of it by e-mail. For example, performing some simple self bondage, wearing nipple clamps for a set amount of time, wearing no underwear etc.