This is a good question. Personification is when you give life like qualities to non-living things. So, if you say that the wall of a house can hear, this would be an example of personification. Another example would be if you say that the sun, moon and stars are smiling down on someone.
Imagery is when a piece of literature conjures up and uses images to make a point, usually a comparison. For example, you can say something like the candle flickered in the dark as a bird flutters her wings. The imagery of the bird flapping her wing helps with the flickering of the candle.
Onomatopoeia is when a word imitate the sources of the sound. Here are some examples: gush and splash.