How to use 如 to make comparisons or analogies
It is more of a literary/formal expression; It's not really colloquial. 

I'm not sure exactly what you mean by making "fresh" analogies. If you mean "Can you make new formal/literary expressions when writing literature?"- the answer is yes. 如 is not bound to any fixed idioms/expressions. With that said, it helps to learn the root meaning of the word so you can use it how you want:

如 itself means "as","as if"


Take the following usage in a "fresh" expression:

天上的星星**如**无数只眼睛，在一眨一眨。
(Tiānshàng de xīngxīng rú wúshù zhī yǎnjīng, zài yī zhǎ yī zhǎ.)

The stars in the skies are **as if** there are countless blinking eyes. 




And 如, as you know, is also used in several fixed word pairs:

如果: if
如何: how
如此：if (more formal)


Hope this helps.