Theory:

A simile is a figure of speech in which two unlike things are explicitly compared, always including the words "as" or "like".
Example:
1. As busy as a bee: Someone who is always busy doing something.
Usage: Since the exams are fast approaching, Jack is as busy as a bee.
 
2. Like peas in a pod: Someone who stays together always.
Usage: Kamila and her sister are like peas in a pod.
 
3. As innocent as a lamb: Someone naïve, gullible or faultless.
Everyone loves Rosy because she is as innocent as a lamb.
Important!
A simile establishes a connection between two things using the terms "like" or "as".
Similes are used to express thoughts/feelings/words in a unique way, which differs from the ordinary tone of speech.

1. It adds to the emotional/expressional intensity to make the reading more interesting.
2. It emphasises the meaning of the thought.
3. It gives better clarity.
4. It adds a beautiful tone to the text.
5. Thereby makes it more attractive to the reader.
Similes used in the poem "A Legend of the Northland":
  1. and the children look like bear’s cubs in their funny, furry clothes
  2. and baked it thin as a wafer
  3. but all the rest of her clothes were burned black as a coal in the flame