Move closer, or away from the front door, take the compass reading from inside the house, then take it from the outside (this is where you will have your back to the front door.) See if there are slight variations in the reading.
If there is a strong presence of iron and steel objects close to you, as in the door hardware, for example, or if you are wearing a heavy metal watch or a belt with ornate metal work, this will disturb the compass reading. You will need to take off your watch and belt or move away from the door for a more accurate compass reading.
So, the reading is taken while you are facing out your main door, because you want to know which direction your house is facing.
Once you have the feng shui compass reading you will need your floor plan. This will help you accurately find the center, or the heart of the space, often also called the yin-yang point.
From there you will define the Ba-Gua, or the feng shui energy map of your space, and will start the journey of changing your life with feng shui!