There are many expressions commonly used in English to express similarity.
There is no magic rule to help you remember them. You just have to learn them. Sorry!
Take a look at the examples below.
To be like a deer caught in the headlights.
This is used to describe a situation where a person is visibly startled and looks so frightened that they are frozen with fear. The person cannot move or think properly.
E.g. After completing his presentation he was asked some really difficult questions. It was very stressful for him and he looked like a deer caught in the headlights the whole time.
To be running around like a headless chicken.
If someone is running around like a headless chicken, they are very busy, moving very quickly but not being very efficient or effective with their time. They are disorganized and not thinking calmly or logically.
E.g. The whole event was so badly organized. Nobody knew who was in charge, or who to talk to when there was a problem. They were all just running around like headless chickens!
Have fun learning English!
Louise