I'm very much a novice in jhana practice--I may have gotten to first jhana once or twice through breath meditation.

After reading Shannon and Daniel's book on the fire kasina, I want to try kasina jhana practice in order to take advantage of the immediate visual feedback.

However, I don't know what to do to transition from access concentration to first jhana. In Brasington's book on the jhanas, he describes concentrating on the breath and then at some point noticing a pleasant feeling and switching the object of concentration to that pleasantness. Should I be looking for a similar experience with the kasina, or do I just stay with the kasina visualization?

In the two practice sessions I've had so far with the kasina, I've managed to stablize my attention on the visual afterimages after about 15 minutes of practice, but I can feel that I hve a lot of tension, especially through my facial muscles. I will be experimenting with using a lighter touch once attention has stabilized, but I don't know if there are any specific shifts I need to watch for.