J = Joking. Do you have a character who is the joker of the pack? If so establish the fact they are like this early on. Are they a joker to cover up huge sadness (in many ways the "standard" reason but a very valid one nonetheless)? Do the other characters find the joker irritating or are they almost therapeutic to the others? Think about why your characters are the way they are. You'll write about them/for them more convincingly if you really know where they are coming from and why.
K = Kindle. I love the Kindle. I love "proper" books too. I don't see the Kindle as a threat, merely as another format (and I hope a way of reaching those who may be put off by the traditional image of books and bookshops). Certainly it is worth having your books out in electronic and paperback at the very least. You will reach more people for one thing. Especially as we come into summer time, people will want plenty of downloads for their Kindle. Why shouldn't your book be one of those? (Mine too come to that!).