Prepare your net

Photo credit: M from COOS

临渊羡鱼，不如退而结网。
lín yuān xiàn yú，bù rú tuì ér jié wǎng
《汉书·董仲书传》《han shū · dǒng zhòng shū zhuàn 》

Rather than admire the abundance of fish [opportunities in front] of the lake, why not retreat to sew your net [to catch the fish].

This proverb was used as a parable from 董仲舒, a politician and a philosopher, who warned the Han emperor to use systematic/benevolent manner to govern a country.

Its about goals and process. Does the goal justify the means/process? While having a grand goal is important, the how to accomplish is equally important.
Otherwise it is akin to “building castles in the air”, an illusion.

《汉书·董仲舒传》，书中说：“故汉得天下以来，常欲治而至今不可善治者，失之于当更化而不更化也。

古人有言曰：‘临渊羡鱼，不如退而结网。’”意思是说，汉朝希望国家能得到很好的治理，却没有达到这个目的，原因在于“当更化而不更化”，也就是没有在观念上、制度上做出必要的改革和调整，于是他借“临渊羡鱼，不如退而结网”这句古训，来告诫统治者，要治理好国家，必须抓住观念、制度这个根本。

“临渊羡鱼，不如退而结网”这一典故，也告诫人们，在目的与手段之间，有明确的目的固然重要，但如果没有实现这一目的的必要手段，目的将是空幻而不切实际的。

Source of mandarin write-up
https://zhidao.baidu.com/question/1302103067889920139.html