Lots and lots of research goes into choosing the right interior designer.
All interior designers will have a unique style or specialty, so you will need to find someone who matches your design identity and with the needs and focus of your project.
From researching interior designers in your local area through design directories and magazines to spending time exploring portfolios online, once you have identified your sense of style and you're overall vision and inspiration for your project, find someone who can make your design dreams come to life.