This seems really stupid, but I see people open boxes wrong all the time. If you are not careful you will either cut yourself or cut the items in the box. It is easy to do correctly, but for some reason everyone does it ass backwards.
1. Get a sharp knife, razor, box cutter, whatever. Contrary to some folks opinion, usually a dull knife is more dangerous since it can’t do its job and as a result is less controllable.
2. Slice under the flaps on both sides of the top of the box while keeping your steadying hand away from that side. DO NOT START IN THE MIDDLE AREA!
3. Lift the top of the box with one hand. This moves the line between the flaps up away from the merchandise.
4. Only after lifting the flaps should you cut the tape between the flaps.
You really need to look into a cheap cutter called Klever Kutter Disposable Safety Cutter. i bought one and they work well.