When writing, we don't tend think about how something sounds--or, I don't. You rarely read a description of someone's voice. Sometimes the accent, but rarely the timber. It is the same thing with the sounds going on in the background. We might be sitting in a coffee shop, but are you focusing on the sound of the espresso machine? The sounds of the coffee beans in a grinder? Probably not.
The most effective way to describe it, though, is to tell the reader the direct sounds--using onomatopoeia. Onomatopoeia means that something sounds like how the word sounds. For example, buzz. There is the word buzz, and it is used to describe the sound buzz. Other examples can include sizzle, bang, and the like. So (going back to the coffee shop), the espresso machine can hiss. Now your reader does not need to picture the sound of the espresso machine; they know exactly what it sounds like. Similarly, if someone snaps the sheets as they wave them dry, the reader knows exactly what sound you mean.
(Onomatopoeia is not an onomatopoeia. This is rather disappointing.)
So, your task for this weekend: in a scene, focus on the sounds. Use onomatopoeia. Describe the sounds of the scene. Hiss! Bang! Crack! Whap! Ooze!