DO: Listen to others , managers, try to remember their name. Dont forget most Indians came from the same boat as you, but do not tell them you are a fresher. Learn things like Outlook, skype, how to do Ad logins, meetings etc. Remember what was asked on the interview, they might quiz you. Dont expect the work to start the same day. Some companies take weeks to provision you laptops and IDs. Some do the same day.
DONT: Dont trust the Indians, they are friendly and will try to get info about you. Dont take curries that smell when microwaved. Dont take other's work on yourself. Respect your time. Some folks just spend extra hours trying to impress the managers. Finish your work and then communicate to your manager.

Also its not the end of the world if you get fired. Best of luck.