Formal:
* आपके बारे में (aapke baare mein) - This is the most common and polite way to say "about you."
* आपकी जानकारी के लिए (aapki jaankaari ke liye) - This literally means "for your information," and is used when talking about something related to the person.
Informal:
* तुम्हारे बारे में (tumhaare baare mein) - This is a more casual way to say "about you," and is used with friends and family.
* तेरे बारे में (tere baare mein) - This is even more informal, and is used with very close friends or family.
The best way to translate "about you" depends on the situation and who you are talking to.