try to carve a swan and at least you’ll get a duck—aim reasonably high and you won’t fall far short
刻鹄类鹜kè hú lèi wù
鹄:天鹅;类:象、似;鹜:鸭子。刻个天鹅不象,不过还象个鸭子。比喻仿效虽不算成功,但还相似。fail to achieve what one set out to do, aim reasonably high and you won’t fall far short