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 eat like a horse.
If someone eats like a horse, they consume a large amount of food on a regular basis.
E.g. You’ll have to make some more. That won’t be enough for him. He eats like a horse.
To fight like a lion.
If someone fights like a lion, they defend their position fiercely with great passion, intensity and bravery.
E.g. They fought like lions until the end.
Have fun learning English!
Louise