Rule #1:
The girl is on the steps.
Exception example:
Where did the man come from?
Rule #2:
She looks like her father.
He works as a waiter.
Rule #3:
He should not have done that.
He should not of done that.
The first sentence is correct, although many English speakers may incorrectly us the preposition of, this is not how it should be done.
Rule #4:
He is different from her.
Rule #5:
She walked into the room.
She swam in the ocean.