Chicks dig scars.
But:
1) Use a sharp blade. They need less force to cut and slip less.
2) Cut away from yourself and any body parts you consider important.
3) Consider where the blade will go if (when) something goes wrong before cutting.
4) try a smaller blade. For handheld cutting/trimming I use a knock-off of this:

The smaller blade (about 1cm or 1/4" of cutting surface) means more control (and hopefully a smaller cut if it does go wrong, haven't tested that theory yet, knock on wood).
The larger no.11 blades are only used for on the mat cuts now.
Points 1 and 2 will also help avoid break the blade and having sharp steel launched at your face and eyes.