What you choose to wear to an interview will influence how you feel, and in affect your confidence.

Look good to feel good.

What you wear will greatly contribute to the first impression you make on the interviewers. When choosing what to wear, think about the impression you are trying to create.
If you look young, and want to be perceived as more experienced, wear a more formal attire.
If you are older, make sure to wear a current outfit, not to create a dated impression.
If your clothes don’t fit you well, are stained or wrinkled, you will present an impression of someone who is sloppy and does not pay attention to detail.
If you want to present a professional image, dress professionally.

Read the blog: The 4 Critical Elements to Creating a Great First Impression.

Dress code can vary between companies. If you want to dress appropriately, but not sure what to wear, it is ok to ask the recruiter/hiring manager inviting you the interview, what is the company dress code. Also do your research, look at the company’s website and social pages for cues. At the first interview look around, notice what people are wearing. For the next interview adapt yourself, but remember that at the interview you are always presenting your best self, so it is always better to be a bit over dressed than under dressed.