Each door is an entry point for energy. During a movement of energy however, it has to flow form room to room via many doors.
It is bad Feng Shui practice to have three or move doors in a row, especially if one of them is a back door and one is a front door. Hang crystals or chimes in between.
When there are doors facing each other, make sure they are of the same width and height that they directly face each other. Two equal doors completely not aligned is also acceptable.
Doors could be opposite to each other, succeeding each other or adjacent to each other. They may be placed in line or offset from each other. Doors which are opposite to each other and not in the line are very bad.
The mutual relationship between these internal doors often controls the energy flow within the area.
If two doors are at right angles to each other, make sure they each open and shut into the rooms concerned and do not open out into the corridor.