I think it really depends on the camera. I always have as much natural light in the room and then the overhead if necessary. I can also change the degree of light I get from my flash. Try different settings for your flash. Do you have an illumination assist on your camera? Make sure that is enabled if you do. It helps cancel out the glow on the eyes. As for blurry I would say try a tripod it will kill the shake of your hand. And if you prefer handheld then try locking the focus. You should be able to lock focus with a half push of button you use to take your photos. But again I think these things depends on the camera overall.

I hope something I have suggested can work to help you.

Good Luck.

Michelle