I think if BTC decrease, which i'll do just simply hold my BTC until the value increases again in market or buy more BTC. it the time to buy more BTC, it's normal things when the value of BTC or other coins decrease in crypto. After the price dump, the value of coin will rise and pump again even surpasses the previous price.
Yes that's the right thing to do but if you really have enough knowledge with trading you can go for marging trading and if you really know that Bitcoin price will go down you can short it and close it if you think it will hit your stoploss you can get faster profit on it but faster loss to if you get leverage on your trade.