Used to refer to the person or persons being addressed.

आप

English Usage: You need to finish your homework before dinner.

Hindi Usage: आपको रात के खाने से पहले अपना होमवर्क खत्म करना होगा।

Used to refer to the person being addressed in a reflexive manner.

स्वयं

English Usage: You should take care of yourself during the holidays.

Hindi Usage: आपको छुट्टियों में स्वयं का ध्यान रखना चाहिए।

Used to emphasize the subject or action of the verb.

स्वयं

English Usage: You need to look after yourself in this situation.

Hindi Usage: आपको इस स्थिति में स्वयं का ख्याल रखना चाहिए।