its very subjective... not all nifty 50 stocks behaves like nifty (index).. during trading if you have a habit of watching index( nifty or bnf) , trade those stocks which follows index behavior those stocks are either weak or strong... for Ex. if the stock is weak and nifty is falling it follows the index and vice versa. Some stocks also follows sectorial behavior also again you should be good at technical analysis and price action/
my suggestion is filter weak (bearish) and strong (bullish) stocks & compare their behavior with index or sector. trade strong stock when index is doing well & vice versa.
hope it helps..!!