What is the easiest literary device?

It's impossible to definitively say which literary device is the "easiest" as it depends on individual skills and preferences. However, some devices are generally considered simpler to grasp and implement than others:

Simile: Comparing two things using "like" or "as" is often straightforward. For example, "The moon was like a giant cheese."

Metaphor: This device directly compares two things without using "like" or "as." For example, "The moon is a giant cheese."

Personification: Giving human qualities to inanimate objects or abstract ideas can be easily understood and applied. For example, "The wind whispered secrets through the trees."

Alliteration: Repeating consonant sounds at the beginning of words creates a pleasing effect. For example, "Peter Piper picked a peck of pickled peppers."

Onomatopoeia: Using words that sound like the noises they represent is quite intuitive. For example, "The bee buzzed around the flower."

Hyperbole: Exaggerating for emphasis is a common and easily recognizable technique. For example, "I'm so hungry I could eat a horse!"

Ultimately, the "easiest" literary device depends on your individual strengths and what resonates with your writing style. Experiment with different devices and see which ones you find most natural and enjoyable to use.