One Indicator you can use for buying and selling is RSI (Relative Strength Index) which gives you the best opportunity of buying and selling if it is lower than 30 it means it is a good time to buy and if it is higher than 70 it means it is not a good time of buying. DYOR
Market doesn't always work according to RSI 30 below to buy & 70 higher to sell, that's beginner level mate.