Hi,
I've certainly found that it pays to spend time chatting and finding out what the student likes. One of my younger ones likes Pokemon, so using a number of Pokemon style games tied together as 'building blocks' i've been able to teach some fairly complex theories for a younger learner. Being able to drip feed theory and technique through play works well too. Lots of games, lots of fun. A dry guitar lesson would bore the pants out of me, so will definitely have the same effect on a student.
Yes, i agree about lesson length. 30mins is nearing the limit for the younger ones. Keep them interested with varied lessons. Last week I did a set of lessons about rhythm with a whole selection of hand drums and things to make noise with in my studio!