A stock trend is pretty obvious. You can see thru a stockchart whether a stock is going up, going down or going sideways. Definition of an uptrend, higher highs and higher lows. A downtrend is the opposite. Lower highs and lower lows. Trade with the trend. If the trend is up, go long, if it is down, short it. Warning: If you trade stocks, do not short stocks. Your risk to the upside if it runs up or gaps up is unlimited! Use put options if you want to short stocks.