Wet Carpet (simile)
"He looked like a big piece of old brown carpet that had been left out in the rain."
When Opal first meets Winn-Dixie he is in very bad shape and has clearly been fending for himself a long time. This simile compares his fur to an old carpet as he has parts of his body where there is more fur than on others, much like the way a carpet wears with more or less thread still on it, and when carpet is left in the rain it has a sodden, moldy smell, again similar to the odor coming from Winn-Dixie.
Bug Under A Microscope (simile)
"She couldn't stand having the ladies at church judge what she was wearing and what she was cooking and how she was singing. She said it made her feel like a bug under a microscope."
Opal's father uses this simile while explaining to Opal why her mother hated being a preacher's wife. She felt picked apart and looked at far too much—not out of friendship but out of a sense of passing judgment, so that she was being studied for scientific assessment rather than glanced at out of interest.
Turtle Shell (metaphor)
"I could see him pulling his old turtle head back into his stupid turtle shell."
The preacher reminds Opal of a turtle who retreats back into his shell whenever a subject comes up that he does not want to talk about, or when he is choosing not to see something that is happening in front of him. Usually, it is in relation to Opal's mother which is why Opal finds it frustrating.
Bowling Ball (simile)
"He just stood there, and Winn-Dixie came battling right toward him like he was a bowling ball and the preacher was the only pin left standing."
This simile describes Winn-Dixie during a thunderstorm as he comes out of the room with such force and barrels into the preacher. The preacher comically falls over because of Winn-Dixie's fear.
Wild Animal (simile)
"I talked to him real soft and gentle and low, like he was a wild animal that I was trying to get to take food out of my hand."
By taking care to be gentle and welcoming in the party, Opal shows how empathetic she is to Otis. He is very shy and almost too frightened to follow Opal into the party, but when Opal treats him with care and coaxes him to come in for food, she helps him overcome his fear. Opal finds a way to include Otis, who had lived excluded from society for a long time.