Use Humour: Instead of scolding the child, use humour to resolve the concerns as a good laugh helps break the tension. Words like, we can work on this, this is nothing serious, can help break the barrier as well as help in disciplining the child.
Use Eye Contact: Eye contact brings out your intent and seriousness related to the concern/matter at hand so instead of calling out instructions from another room, it’s much better to walk into the room with the child and make sure that he/she is looking at you with full attention.
Walk Away: The message of your body language should be that you have full confidence that your child is going to comply with what you just said. If you walk back through the room and it hasn’t been done, give a warning of the consequence. Then, walk away.
Stop Talking About It. Use one word reminders and quit nagging, placating, lecturing or preaching. Ensure that your expectations are clear, concisely worded and the consequences are understood. If need be implement consequences dispassionately and without dialogue/discussion.