The old joke goes: A simile is like a metaphor. (I didn’t say it was a good joke.) The most obvious difference between a simile and a metaphor is simply that metaphors leave out the comparison words “like” or “as.” In that sense, a metaphor is an indirect comparison. It compares two things by saying one thing IS another: laughter is the best medicine, love is a warm puppy, children are the future. And clearly, a metaphor can become cliché as easily as a simile. Keep them fresh and stimulating:

“All the world’s a stage, and all the men and women merely players.”—As You Like It  by William Shakespeare

“I am the good shepherd, … and I lay down my life for the sheep.” – The Bible, John 10:14-15

“Let us be grateful to people who make us happy, they are the charming gardeners who make our souls blossom.” – Marcel Proust