见微知著
observe small clues that may indicate what is coming;recognize the whole through observation of a part
见微知著jiàn wēi zhī zhù
微:微小;著:显著、明显。看到事物的一点点细微之处,就可以知晓事物发展的趋势和方向。from one small clue one can see what is coming, from the first small beginnings one can see how things will develop