Traders and investors should keep an eye on several key stocks to buy and sell, including Mazagon Dock Shipbuilders (NSE: MAZDOCK), ITC (NSE: ITC), EaseMyTrip (NSE: EASEMYTRIP), Hindalco Industries (NSE: HINDALCO), Shriram Properties (NSE: SHRIRAMPPS) and RVNL (NSE: RVNL) on December 31.