Liberally anyone can become an interior decorator. Some one who loves playing with colors, fabrics and textiles can be a decorator by simply printing business cards and promoting themselves to clients. This is not necessarily a bad thing, but educational background is also important.
In order to be an interior designer, you need to have innate flair for color, spatial arrangements, architecture and textiles. The first step to a successful career is to follow your passion. After all, doing something you love will never fee like work. Interior designers need to be educated in history of design, the structural integrity of buildings, building codes, ergonomics, spatial concepts, ethics, psychology, computer-aided drawing and much more.