I'll leap from the top rung to start it seems...

I am quite new to this myself, both the forum and lifestyle. My wife and I had a sort of 'rediscovery' of our sex life this summer, and with our newfound lust we experimented and soon discovered bdsm. It quickly became obvious that she was a sub, and I enjoyed being a top, but I've had to work at being in charge. But, enough of my prehistory (short though it is) as for training: I would imagine training (in a bdsm setting) involves modifying behaviour, both subtly and obviously. For example, I've made a point of spanking my wife every now and then, both alone at home and publicly between shelves in stores and so on. This has made her tense up in anticipation whenever I come up behind her, even though I often don't intend to spank her. We both find this quite arousing with her always expecting a slap, never quite knowing if or when it comes. This also becomes a sort of game where I try to catch her unawares, making it all the more pleasurable when I do...
Another thing I do is tell her I've made some sort of plan for a session in the future (near or distant) and give her hints about what it may or may not involve. This way, I can drop small hints, both actual and false ones, just to gauge her reaction. Seeing her tense up and get goosebumps or hard nipples simply by showing her a lit candle and give her a knowing look is quite a lot of fun...

Hope this helps, and if anyone else has similar ideas, please educate me.