Here is a simple trick I use for securing my camera to my hand while shooting. Please excuse the snapshots. I was shooting my K10D and pop up flash left handed and triggering it with my index finger while holding the K100D out to illustrate this post. The blurring is intentional. It was the only way I could obscure the fact that I wasn't using a professional hand model.
Caveats aside this trick will make your camera feel like an extension of your arm. Your shots will be steadier, your camera will be safer, you will have more energy at the end of the day and you will never end up with another one of those pictures where your camera strap gets blown into the frame at the wrong moment (am I the only one that ever happened to?).
First I cinch the buckle on one side all the way up against the camera body. Then I add hook and loop velcro at these locations:
Be sure the hard, hook side, of the velcro is on the camera body and the soft, loop side, is on the strap, or the hooks will play havoc on your polyester leisure suit. When shooting I grab the body, slip the strap off my shoulder and let it drop over the top of my hand like so:
As I'm lifting the viewfinder to my eye I wrap the strap under and over my hand and press the velcro together to lock it to my hand. No comments on my needle work please. I'm no seamstress. That's 90 pound spider wire fishing line right there (que chest thumping and masculine grunting sounds).
Most of the time that's it. The weight of the camera is now being carried by my wrist and forearm rather than my fingers. It's very comfortable and secure.
If I am loaded up with a big flash or heavy lens then I will go one step further, wrap it underneath and double secure it with the second set of velcro tabs.
Viola! There's your 15 cent wrist strap. Easy on the hand, easy on the pocketbook. I can now shoot all day and my hand never gets tired.
It's fast and easy to get in and out of too. If you are going to set the camera down pull both tabs loose, shift the bottom tab back and stick it to the top one. You now have a big fat loop waiting for you to stick your hand back through to cinch it down and keep shooting. All of this will quickly become one fluid motion as you lift the camera to your eye. You won't even think about it - Happy shooting!