A little tip to seiza, put ALL of your weight on your right foot, bend your left knee, and slowly go down. Put more weight on the calf/shin rather than your knees. Then put your right leg down. Try to have your feet point "inwards", rather than "outwards". It helps a lot. I try to "practice" seiza - just sit at home in seiza once in a while and get used to it. I've done like 30 minutes, tops. Need MORE KENDO!