Simile

Similes are comparisons between two unlike things using the word “like” or “as.” a simile connection is not the equivalent of an equal sign. Instead, it is meant to highlight a similarity and suggest that one thing is like another. 

1. Don ate his salad like a vacuum cleaner.
2. His arms were weak and felt like noodles.
3. The thunder was as loud as fireworks.
4. This house is as clean as a whistle.
5. He is as funny as a barrel of monkeys.

Metaphor

Metaphor is a figure of speech which makes an implicit, implied or hidden comparison between two things or objects that are poles apart from each other but have some characteristics common between them. In other words, a resemblance of two contradictory or different objects is made based on a single or some common characteristics.

1.The smoke was cotton balls billowing from the chimney.
2. You are my hero.
3. The sun was a furnace.
4. The news has hit him hard.
5. I don’t want to put any ideas into your head.

Allusion
Allusion is a brief and indirect reference to a person, place, thing or idea of historical, cultural, literary or political significance. It does not describe in detail the person or thing to which it refers. It is just a passing comment and the writer expects the reader to possess enough knowledge to spot the allusion and grasp its importance in a text.

Examples of Allusions:

1. Your backyard is a Garden of Eden. (Biblical allusion)

2. I guess I should see this message about a new job as my burning bush. (Biblical Allusion)

3. When you feel betrayed by a friend, you can say, "You too, Brutus?" (allusion to Julius Caesar-Brutus betrayed Caesar)

4. You're a regular Einstein. (allusion to a historical figure)

5. When your parents learn about your new plan to raise money, it's going to sink like theTitanic. (allusion to a historical event)

6. You are carrying the weight of the world on your shoulders. (reference to Atlas in myth)

7. That man is so narcissistic. (reference to Narcissus in mythology)