The smell of salt air and a warm afternoon wafted through the sky.
One option is to organize your essay from general to particular.
For example, if you were describing the new Big Tex at the State Fair of Texas, you might start out by describing the setting - the smell of the corn dogs frying, the crowds of people, the happy children dodging in and out of the midway games - then get into his grandiose size - after all, everything is bigger in Texas, right?
A metaphor has the same function as a simile, but the comparison between objects is implicit, meaning there is no 'like' or 'as' used to signal the comparison.
Here's an example of a metaphor from good old Shakespeare: 'All the world's a stage and the men and women merely players.' Rather than saying life is just like a play, he compares the world to where a play is acted out.
As you can see, this structure works particularly well when the subject of your essay is an object.
If the subject was the entire State Fair of Texas rather than just Big Tex, you might choose to organize your essay spatially.
The warm sun brightly shone on my face and greeted me, 'Good afternoon'.' Based on this paragraph, where is the author? Thanks to the five senses, you can gather that he or she is just waking up from what seems like a really peaceful nap in a hammock on a beach somewhere. Based on the description, we can see waves hitting the shore as the tide comes in, hear the water as it hits the sand, smell the salty air, and feel the warm sun.
See how the senses use concrete things we've all probably experienced to some degree in our own lives to help you visualize a new scene?
You can describe a feeling, a sound, or even an emotion.
Descriptive essays are just the same: they help you illustrate something in a way that your reader can see, feel, or hear whatever it is you're talking about.