Mahdieh Mohammadkhani's different outfit in her concert in Germany
If you don't want to wear formal clothing, then try wearing denim jeans with cute tops in neutral colors like black or gray, paired with sneakers in either silver or gold heels. Also, do not forget to accessorize yourself by wearing pretty hairbands or headdresses that go along with the theme. You can also search online for some ideas, for example, if you are going to a country music concert you can search for “great country concert outfits” and see what they have chosen. This will help you understand how to dress for different types of music.