it is difficult to predicting when the price is fall but we can try by watching and analyze in the market because if the price is down sometime it will going down for more so we can make buy order. but for people which don't want to buy, they can prepare to sell their bitcoin if they are thinking that they don't make any profit at all and they can prepare to wait in lower price to buy again. i think in out there, many of the news will spread about bad news that will make people getting panic and they selling their bitcoin with fast, so be careful and make sure you can sell at the price you want.