When to buy and sell?

I personally look at the historical graph and the 5D graph to see if the stocks is in it's peak or dip. Also to check on the stocks shorted amount. If it is heavily shorted, there may be a rise soon. From the inferred data to determine if it have dipped to a great price before buying. Though it does happen that the price dipped further even after the dipped. For selling, it depends the possibility on how much the stocks is able to rise in a day in a period of time (referring to highest amount as well as amplitude metrics) , and try to sell at the best possible price. From experience, not to chase the stocks and only buy and sell when it reach the intended price, not to rush :)