Effective communication is a delicate matter. Politeness is a critical factor in having questions answered and successfully communicating with other people. On the other hand, being polite is only one part of the equation. Being too firm in your approach can turn someone off, while coming across too subtle may not suffice in articulating your point. Politely asking about the progress of something is a straightforward process -- if you follow these simple steps.
Approach a person at an appropriate and convenient time. Choose a time when the person is calm, pleasant and able to talk. Do not interrupt someone if they are involved in other tasks or busy with additional projects. Asking a question at the wrong time can engender frustration and pollute the answer.
Ask a personal question -- about work or family, for example -- before inquiring about other issues. Pose the question in a genuine manner and really listen to the response. Disarming the person with a personal question releases their defences and puts you both on common ground. Listen carefully to the response to confirm if it is an appropriate time to continue with your other inquiry.
Look the person in the eyes and present positive, open body language. Keep your voice steady and smile. Ask your question directly and clearly. Do no exaggerate nor understate your needs. Stay courteous and be ready for any answer. Maintain positive body language and be prepared to ask easy -- albeit direct -- follow up questions and acquire any other possible information. Thank the person for their time and information and wish them well.