Most Portuguese learners get saber and conhecer wrong, simply because they mean kind of the same thing in English.
When to use saber?
Use saber to talk about information or facts, or to talk about something you know how to do.
Oh... And the verb that follows saber is always in the infinitive form.
Saber can be understood as "I'm knowledgeable about it."
Você sabe o preço de uma passagem para São Paulo? Do you know the price of a ticket to São Paulo?
Eu sei tocar piano I know how to play the piano
When to use conhecer?
Use conhecer to express acquaintance with people, places, or things.
Conhecer can be understood as "I'm familiar with."
Eu conheço seu pai I know your father
Ele já foi à França e conhece Paris muito bem He has already been to France and knows Paris very well