Practice, practice, practice. Here are some more thoughts:
-Spirit: The last practice we worked on keeping our spirit really high, and this helped immensely with my technique. After doing Kirikaeshi, Sensei pointed out that it was the best he'd seen us do it so far (there were a handful of us in the class at the time). He said that when we concentrated on Spirit and keeping it high, the rest of our techniques fell into place. Not perfect, but loads better.
-Maai: I still need to work on my distance. Hitting with the tip of the Shinai. I need to use that reach and the full length of the sword. The further out I can hit from, the better advantage I will have. I catch myself thinking about this a lot, and I'm working towards a point where it will come naturally.