The double denim style also known as the denim on denim is a hot trend any day. Wearing denim on denim is a good combination for a casual look.
You can decide to opt for the same colour both as top and bottom. You can also decide to combine two different shades of denim. However, it would be ideal to wear a darker shade as the bottom and lighter shade on top.
Then complete your look with a lovely pair of high heels, wedge or flats as you desire. See different ways to rock the denim on denim style.