Personification is where something that isn't alive is given human qualities. For example:
The wind whispered in her ear.
The wind cannot physically whisper because it does not have a voice, but by describing the wind as "whispering", we understand that it is making a quiet noise similar to a whisper.
Alliteration is where the beginning sound of a string of words is the same. For example:
The kind cat kissed her kitten.
Note that the words do not all start with the same letter, but they begin with the same sound, which makes them an alliteration.
Simile is where two things are compared using the words "like" or "as". For example:
The drum was as loud as a clap of thunder.
This gives us a reference to help us imagine exactly how loud the drum was, because if we only said "the drum was loud", it would not be nearly as descriptive as comparing it to thunderclaps.