Practice kitchen manners and say it loud.
"Behind you" goes a long way. Nobody wants to give you a lecture filled with excuse me when you're holding onto something heavy, hot and can scorch you with the wrong move. Behind you is a nice way of asking you to clear the space. Don't take it as a person trying to be rude...just move out of the way. Offer some help if you can extend it and it's practical. Scream out "sharp" when you have a sharp object. I don't want to be on the ten o'clock news because I was stabbed in the face accidentally. Plus, hold the items down when carrying these objects. Hand over a sharp object with the handle facing me. I need to effectively grab it.