To paint a dragon and dot in its eyes
To add detail that drives home a point or brings a piece of work to life. Generally refers to artwork, speeches, and writings.
Positive
没有你画龙点睛的一笔，这幅画还真没什么看头 | Méi yǒu nǐ huàlóngdiǎnjīng de yī bǐ, zhè fú huà hái zhēn méi shénme kàn tóu
Without your finishing touch, this painting really wouldn't be anything to look at
[Source]
最后的这段话十分精彩，在文中起到了画龙点睛的作用 | Zuìhòu de zhè duàn huà shífēn jīngcǎi, zài wénzhōng qǐ dào le huàlóngdiǎnjīng de zuòyòng
This last paragraph is excellent. It really serves to drive home the point of the point of the paper.
[Source]
Finishing touch
None
None
《历代名画记》(Lì Dài Míng Huà Jì), a work by 张彦远 (Zhāng Yànyuǎn) in the Táng Dynasty (唐, 618 - 907 AD)
During the Liáng Dynasty (梁, 502-557), there was a famous painter named 张僧繇 (Zhāng Sēng Yóu). At the time, the emperor was a Buddhist, and he asked the painter to draw four dragons onto the walls of one of his temples. 张僧繇 completed the task in only three days, and the exceptionally life-like paintings drew the attention and admiring gasps of many people. However, when people got up close to the paintings, they noticed something was missing: none of the dragons had been given eyes. When they asked why, 张僧繇 explained, "It's easy enough to paint eyes, but if I do, then the dragons will come to life and fly away." Everyone thought he was lying and continued to pressure him incessantly, and eventually, he gave into their demands.
When the painter finally gathered his paint and paintbrush and went to finish the job, many people assembled to watch him. He worked very slowly, and when he finished adding eyes to the second dragon, something strange happened. Dark clouds covered the sky, wind started howling from all directions, thunder roared, and lightning flashed. In the next moment, the two completed dragons burst from the wall, and, with glowing eyes and bared teeth and fangs, flew off to the heavens. The assembled crowd was left utterly speechless, and their respect for 张僧繇 grew even greater.