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 grin / smile like a Cheshire cat.
If someone is grinning or smiling like a Cheshire cat they are smiling broadly, smugly and widely often because they are feeling very pleased with themselves.
(This was made popular by the character in Lewis Carroll’s Alice’s Adventures in Wonderland.)
E.g. We weren’t sure at the start who had played the joke on us until we noticed Simon grinning like a Cheshire Cat. We knew then it was him.
To spread like wildfire.
If something (e.g. information or a disease) spreads like wildfire, it reaches a large number of people in a short space of time.
E.g. Rumours about him being fired for bad behaviour spread like wildfire. Everyone in the building knew by lunchtime.
Have fun learning English!
Louise