I usually try for a progression of techniques within some constant value when I am teaching. That is, I will decide that on some particular class I am going to work on ikkyo - - and I will start with basic attacks (shomen-uchi or kata tori... etc) and move to more elaborate ones as the class goes on,depending on what level the students are capable of. Alternatively, sometimes the theme is the attack, and I will try to teach multiple defenses all against the same attack. Rarely I might concentrate on something else, like a particular tai-sabaki, or breathing, posture etc for the class, with fairly random techniques selected out.
I guess my general aim is for students to see the connections and flow between techniques, and eventually not think too much about anything specific.