I think maybe you could start out by writing a cliche metaphor or simile, like “Her eyes, as blue as the ocean, shone.” Then you can expand upon that cliche metaphor and change it to make it not cliche, while still keeping the same sentiment.
For example, you could write “Her eyes, as dark navy as the boiling sea before a tsunami, glistened in the blooming light.”
That way, you still keep the original idea of the metaphor or simile, but the new metaphor or simile is less obvious and more creative.
So basically, my tips would just be to write a cliche, very obvious metaphor or simile, then expand upon it and revise it in order to make it more unique.
I hope that helps! Good luck! :)