The following are examples of adjectives of equal rank describing the same noun (note the use of a comma as well as the ability to exchange their locations in the sentence with one another):
The sad, bedraggled traveler could not believe her flight was canceled.
The dangerous, preoccupied driver weaved through the city streets viewing his phone.
The following are examples of adjectives of unequal rank describing the same noun (note the lack of a comma as well as the inability to exchange their locations in the sentence with one another):
Several happy people danced in the streets upon hearing the news.
We examined the many unique pieces of art work hanging on the walls.