What are examples of similes?
If you compare something to something else, it's a simile.
To use a simile is to say something such as, "She was as bright as the sun." The defining trait that makes it different from a metaphor is the word "as". If it was a metaphor, you'd say, "She was the bright sun." Instead of just comparing them, you're making a direct relationship between the two, 'she' and 'the sun'.
So, make sure you include 'like' or 'as' when doing similes.
If you're still confused or in need of more examples, try this site.