I've put the L shaped finger guard protectors on my long rulers and they work well. I also have the rubber gripper dots (sandpaper ones don't work as well) on all of my rulers so they don't slip. Cut in good light when you aren't tired and make sure that everything is set up for your dominant hand. Invest in a revolving mat if you are trimming up blocks so you won't be running around the table or trying to cut on the wrong side of your ruler. Focus on what you are doing and avoid distractions (this isn't the time to have an argument with DH). Use a sharp blade as the dull ones require more pressure and may slip cutting you. Good luck with all of this.