If there is something that you believe strongly in, you should stand up for it. By putting your feet in the right place, you are making sure you have a valid argument, point, or belief system. Some examples of these would be politics, religion, human rights, animal rights, etc. These are sometimes controversial subjects, which many different people have many different views. Your view would be considered where your feet are, someplace you believe to be "the right place". By standing firm, you would stick to what you have to say about your subject. You would want facts and statistics to follow up what you are saying. If you feel strongly enough about something, not backing down, and no one is going to change your mind, you are standing firm.
