Augmented Reality (AR) has been proved useful to guide operational tasks in professional domains by reducing the shift of attention between instructions and physical objects. Modern smartphones make it possible to use such techniques in everyday tasks, but raise new challenges for the usability of AR in this context: small screen, occlusion, operation "through a lens". We address these problems by adding real-time feedback to the AR overlay. We conducted a controlled experiment comparing AR with and without feedback, and with standard textual and graphical instructions. Results show significant benefits for mobile AR with feedback and reveals some problems with the other techniques.