I do not like to hang camera around my neck. Therefore I use hand straps on my cameras. However, it is not easy to find a strap that not just ensures camera from dropping but also provides an extra stability for shooting. Now I found a Micnova MQ-HS4 hand strap, which seems to do what I want, but I just had to tune it a little at first.
First of all attach the bottom part slightly angled. This way I get good solid spot to press against the palm of shooting hand. On Canon G12 this also solves the problem of accidentally pressing menu button located on bottom right corner of the camera.
Then I removed the hand cushion and reattached the strap in a single large loop. To use it I just put my hand though the loop from front side of the camera, twist the hand, and take a hold on camera. That way the strap gives a firm hold around the wrist and palm rests against the bottom socket.
You can also put the middle finger under the strap to get a firm hold also on top corner of the camera.
This hand strap was rather expensive. I bought mine from local Finnish Rajala camera shop, which ofcourse makes it even more expensive than buying it from some online shop. So, you may wish to seek for something more inexpensive or better solution for you. But for me and for my large hands this seems to be an ideal solution, making it easy to keep camera steady and secure even with one hand.