For me it is impossible to predict which limit the coin will rise and the limit where the coin will go down and you must know that it is almost impossible to buy or sell coins at a perfect price. So, I think you should always try your best, rather than always trade with doubts.
the reason why it is hard to predict and go trade with certainty is that there are just too many traders and coin buyers around the world and it is just too hard to interpret or read each of the minds of these traders.
but there is a way to get through it and that is by consistently trade on a particular coin and note its trend and you could get through by doing this.