We use it when the second term of the comparison is a noun, a gerund or a pronoun.
Dave looks like his father. - Don't act like me !
Tolearnenglish is like having your own private tutor.
Like can be modified with adverbs , such as :
just, more, very much, not at all... :
Just like you, Jane wanted to be a doctor.
We use it when the second term of the comparison is a verb, a clause or a preposition.
Don't do as I do !
It started raining, as I said it would.
Prices are very high, as in the 1990s. (as they were)
As can be used before a noun:
She works as a nurse.