I would second the notion of knowing the tartan and a little of the history it represents. Not that it really matters but a lot of kilt wearers really get into the history of the tartan and clans and may want to chat you up. It will also help you understand the jibes made in jest (I think?) about other clans. Caution some of the history wasn't pleasant, my own MacLeods and your chosen MacDonalds weren't the best of neighbors (it could still be said of me by some ;) ) and some may say that there are still proscriptions about tartans due to this. Personally at this late date I would say that those folks need to get a life. But as in most things the more you know the more you enjoy.