Interior designers need to have a sense of style (that is pleasing to the eye). Which that can come from different aspects, like:
Creativity
Visualisation
Outside-the-box thinking
Interpersonal skills, like leadership and responsibility.
Adaptation
Problem Solving
A can-do attitude
*Note: It is not a requirement to have all. They too, don't need to be perfect. You may feel comfortable with some than others, but creativity is one that you must have.
To become a professional Interior designer in NSW, an HSC or higher school certificate is needed. They also need to have recognised tertiary preparation certificates, certificate IV level or higher vocational qualifications. Along with a complete one-year full-time study (minimum) or its equivalent in a degree course at a higher education institution.
There are also different pathways to becoming an interior design, for example:
At uni, you could take a foundation degree, higher national diploma in relevant subjects of interior design, art and design, interior architecture and spatial design
You could take various relevant courses in college
A furniture design technician (a type of advanced apprenticeship)
...to get into interior design.
Spatial Design