Here's a dry land kayak rolling practice technique that you can do almost anywhere and stay completely dry. This is just the beginning of the sweep roll movement, but it is arguably the most important part to get right.
Remember to follow the paddle with your eyes from the very beginning to the very end. If you don't open your eyes, then follow the paddle with your face.
Good luck, and I hope this helps.
I also found two other YouTube videos showing the same technique in slightly different ways. Both of these demonstrate using this for the "C to C" roll, but they should be helpful regardless of which roll you prefer.
http://youtu.be/FOUGaBIlF70
http://youtu.be/Du-MqOOre2c
