If your front door is the gateway for Chi to enter your home, it is the mouth of your home. Sometimes we consider that we have 2 front doors. One that was designed originally by the architect but we may have a preference for using the side door or a kitchen door on a regular basis. I would consider that it is the door that the architect or builder designed and built. Having 2 front doors can often cause unnecessary arguing and bickering and dithering amongst the occupants.
Make sure that the name of your house or the number of the street is clearly visible for all to see. In the evening, is it well lit? The clearer the identification is, the better it is for your career, for your recognition and for ensuring an active social life. When guests visit you, it would be the perfect introduction if, on all levels, they felt uplifted by entering your home. On a sub-conscious level, even how you position the number of your house can have a subtle effect. For example, if the number of your house is 22, then consider positioning the second 2 slightly higher than the first, giving an "uplifting quality" as it is read.
For real support and protection, your front door needs to be solid. Glass panelling above the door or in the higher sections of the door are fine except in situations where Sha Chi (poisoned arrows) is being aimed at your front door. Front doors need to open inwards, allowing beneficial Chi to enter your home. The front door also needs to be larger than the back door encouraging Chi to enter through this aspect. The size of your door also needs to be proportional to the size of your home. If it is too big, you could lose opportunities and if it is too small, then the occupants are likely to argue and bicker. If a front door is made up of 2 panel sections, then they need to be identical in terms of colour and design. Irregularties can lead to confusion and arguments among the inhabitants.
Keep the door clean, freshly painted and the hinges and locks need to be regularly oiled. Imagine opening your front door for someone and it squeaks like the door on Dracula's castle! Deep down, it doesn't give your visitor a welcoming feeling! Make sure that your front door bell is easy to locate and works. I've often been surprised on consultations how frequently door bells do not work and there are even helpful little "post its" suggesting that you need to bang loudly!