I remember when my brother was 17 years old and going for his first job at Rapid Messenger Company. He left in tye dye jeans (A fad in the 70’s), a rock and roll tee shirt, and a bandana in his back pocket.
My mom stopped my brother and told him that if he wanted the job, he has to dress like he was going to a wedding. My mom continued to explain to my brother that it is her generation that will be judging and hiring him. It turns out that she gave him good advice, because my brother landed the job.
Over 40 years later, there is still no better advice. You can never over-dress for an interview. Men should wear suits, ties, and dress shoes. Women should wear business clothes as well. Let the employer tell you the dress code.
Do not have dress clothes? Then go out and buy some. There are discount stores, second hand stores, and many places where nice clothes can be obtained at a low cost.
Dress your best and look your best when you go for your job interview. This will go a long way to landing your job.