How to identify rhymes in a Tang poem? I was reading the following poem by Meng Haoran, whose translation is still troubling me. For a start I thought, I should identify the rhymes. 

李氏园林卧疾
唐代：孟浩然

我爱陶家趣，
园林无俗情。
春雷百卉坼，
寒食四邻清。 
伏枕嗟公干，
归山羡子平。
年年白社客，
空滞洛阳城。


Naively I was sure the rhymes should be 情，清，平，城. However, I thought there must be a way to test this. I know different rhyme dictionaries were developed by the Ancients, as the preferences changed over time. I thought 廣韻 was a famous one and I was lucky to find this digitalisation  online. I found the character 清 and was directed to the corresponding page of the dictionary. I expected a list of rhymes to 清， but I guess the result is something different, since there are lots of sentences like 「山海經曰⋯」. Some characters are printed bolder than others, but below them seems to be something other than a complete list of rhymes.

So, how exactly to use the above or an other book to test if 清，情，平，城 were considered rhymes during Tang or at least Song?
In the character's zdic entry, there is a section labelled 音韻方言, which will have the character's rime group (韻目). In the 廣韻 section, 城 is labelled under the header 清. Ctext further has a more organised version of 廣韻, which you can quickly Ctrl+F your way into 清, which will list all the characters under that rime.

If you have some knowledge of other Chinese languages, or some understanding of how Sinoxenic vocabulary works in Japanese/Korean/Vietnamese, you can corroborate the fact that, at least in some non-Mandarin pronunciations, those characters that you listed did indeed rime.

Interestingly, 清 and 靑 did not rime in Guangyun, as evidenced by the fact that it had its own rime entry.