Keep your blade sharp so that you have to apply less force while cutting. This means less chances for the blade to slip from the working surface.
Always cut away from you, keeping the edge of the blade facing away from your body and hands, and pulling the blade away--never toward--you.
Always store and transport your Exacto knife with a cap on or in a container that will not leave the blade exposed.
Always dispose of your old blades in a different container from your other trash. Mixing blades and trash can lead to accidents during trash removal. Make sure to empty your blade container frequently to avoid overflow.
Always keep the blades in the proper handles or holders. Never try to use the blade alone without its handle, as holding the blade by itself is very dangerous.
Wear gloves for safety when using an Exacto knife. A heavy work glove will prevent a slipping blade from cutting your hands.