A figure of speech uses words non-literally for effect or emphasis, not in their ordinary meaning. Quick test: if the words stop being literally true but still make sense, it is figurative. Her smile lit the room works despite a smile producing no light.
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Simile compares two things openly using like or as. Clue: those words appear in the sentence itself. Her voice was as smooth as silk.
Metaphor compares, but drops like and as and states the link directly. Clue: one thing is called another. Her voice was pure silk.
Personification gives human actions to non-human things. Clue: an animal, object, or idea does something only people normally do. The wind whispered through the trees.
Hyperbole exaggerates far beyond the literal truth for emphasis. I have told you a million times.
Alliteration repeats the same starting sound in nearby words. Clue: say it aloud and the consonants echo. She sells seashells by the seashore.
Onomatopoeia uses a word whose sound imitates what it names. Clue: the word sounds like the noise itself. The bacon sizzled in the pan. Borderline words like chirp are best judged by ear: if they still imitate the sound for most readers, count them here.
The quick test from the meaning side misses sound-based figures. She sells seashells stays literally true, yet alliteration counts as a figure of speech. So refine it: ask whether the words bend meaning, or are arranged for sound or structure. If either holds, you likely have a figure of speech.