I posted this elsewhere but thought it might be appropriate for Mike's forum.
"Kata is to be done in an air of distrust."
-Shuzuk ****ama, 16th dai-shihan of Sosui****su-ryu.
From the moment of bowing in for kata, you and your partner are professional warriors whose only goal is to kill one another. You must have that mindset to properly execute or understand the kata.
When you begin the kata, learn the moves. As uke, you must learn the attacks properly. They must be executed so well that if Tori fails to respond he will be severely injured. Also as uke, you must carefully learn the ukemi. Several of the falls are counter-intuitive in that someone who is trained to fall will attempt to slap out with the controlled arm or dislocate an extra joint in rolling.
After getting a basic understanding of the moves and developing skill, you will progress fastest with a partner who you trust. You must trust him to kill you. Literally. In order to develope the timing and mindset, you have to be absolutely sure that your uke will not attempt to pull the blow or in anyway change his attack to prevent harm to you. Once you are absolutely sure that he will drive the boken (or shinto, later) through your skull, you begin truly learning.
Timing is critical. Not the sequence or rhythm of the moves, especially, but the waiting. Tori must wait until uke is fully committed to the attack. Tori must wait in absolute stillness until it is nearly too late and then move explosively and decisively. In this way, Tori learns how much time there is in a heartbeat, and something of how to control his own perception of time.
Uke dedicates himself to the pre-arranged attack of kata, but if he detects the slightest mis-timing in Tori, uke immediately alters the attack to take advantage of the opening created.
This is general advice about how we do our kata.