That's pretty basic but as a trader we have not master that yet, it requires great knowledge and skills to be able to initiate that right.
Zooplus is right with this one. It is easier said than done. Who knows where the flow goes. We say we will buy when the price goes lower but when will that be exactly? No one knows.
I have tried to that. Waiting for so long just so I could buy cheap but failed.
Same with the selling part. I waited for the max profit but still failed and the bitcoin price fell a little. The best thing to do is just hold it and get the large amount of profit when the value sky rockets.