Obviously it involves some luck and you can't know everything - but you can make a guess based on what you see happening that the price will go up for a little

Obviously it involves some luck and you can't know everything - but you can make a guess based on what you see happening that the price will go up for a little bit before going down and that guess isn't made in a vacuum. In this case there was an enormous amount of hype and articles had just started pouring out about it with the price jumping from $47 up to $88 very quickly. It seemed likely it would increase for some time before the drop. I'm not saying I just used 'common sense' (which is a bullshit term), but that you can make a guess about what will happen and then just cash out immediately when things start to turn south. It has nothing to do with being smart - just paying attention, making a guess based on what's going on and getting a little lucky.