If your looking to lets say cut a loss if you think the run is over learn about the macd because it can help figureout if people stop buying the stock (histogram) on the macd histogram is blue you buy when the brown line (signal line) crosses and then sell when the signal line crosses down (you can also sell when the histogram buying dies down) its alot safer :) heres a picture > https://imgur.com/a/PK9Gg this was mosy in premarket for an example!