If you've downloaded video or picture book recipes from this site that require any cutting with a knife, you've probably noticed that my fingers on the hand anchoring food to the cutting board are always curled as shown here.   

The reason I do this is not to make me look like a chef - I'm not. I only do it to keep my fingers on my hand where they belong. Curlling your fingers does two things: it gives you the firmest, best grip on the food you're cutting and also allows your knuckles to work as a knife guide whether you're using a fat bladed (chef's) knife as shown above or a short bladed (paring) knife as shown below.

Let the flat side of the knife blade rub against your knuckles just like you see here,...

...and there's no way you'll cut yourself. If you're new to this technique, try it a few times and start out cutting slowly.  Use both your hands as a unit as you cut from right to left if you're right handed like me or...

...left to right like this if you're left handed. 

Really feel the knife blade against your knuckles as you cut.  Once you feel comfortable doing this slowly, you can ramp up the speed. In no time at all, curling your fingers will become habit - a darned good finger-keeping habit.