Yesterday, I put together this:
This hour-long audio clip of riding a horse through the stormy night took 14 sound effects, consisting of rain, horse hooves, thunder, etc.
For this long audio clip, I did it in multitrack, and it took ten tracks.
Here's an image of the multitrack:
On the far left, you can see all the audio files used in the multitrack. I get all my sounds from many different libraries online, and when I download them, I keep them in my own library. There were a lot of key sounds needed that most people wouldn't think would be important, but if they weren't in, you'd know it'd be missing them. For instance, for the horse, I first only added horse hooves. But then I thought it needed something with it, as it sounded as if you were riding it bareback. So then, I found a sort of "jingling" metal and item movement, to make it sound like a saddle or other items on the horse as well.
Then, of course, there was the ambient storm going on. I used about 5 different sound effects, including wind, rain, and thunder. Combined, I think it sounds great. Plus, the horse hooves' sound effect was on a mud surface.
Note: I've realized that if you want to make an audio piece sound like night, just add crickets and heavy wind.