Saber is for facts and skills: what you can state or do. Conocer is for familiarity: the people, places, and subjects you have met or been to.
Where the choice changes the meaning
| Context | saber | conocer |
|---|---|---|
| People | Not used with a person as its object. | Conozco a María — takes the personal a. |
| Places | Sé dónde está — you know the fact. | Conozco Madrid — you have been there. |
| Facts | Sé que llegaste — introduces a clause with que. | Not used. |
| Skills | Sabemos cocinar — saber plus an infinitive. | Not used. |
| In the preterite | Supe la verdad — I found out. | Conocí a su jefe — I met. |