Alright then...
My sister dear, in wild woods
Wandered far from home. (Yavanna wandered in the woods of Middle Earth, very far away from Valinor)
My lord and husband always would
Follow her under stary dome. (Orome, her husband, was the other one who wandered there)
I, in golden gardens blooming (the gardens of Laurelin)
Happy danced with sister-in-law, (Nessa, the dancer, was Orome's sister)
While songs, from tiny beauties singing, (tiny beauties being birds)
Mingled with the raucous caw. (caw from a crow, another bird - "the birds sang at her passing")
Famous I am not, for no great deeds
Have my hands performed. (Well, yeah)
But one who left my side for a steed (Arien, for her "steed" the sun)
Is everywhere beloved. (Well, everyone loves the sun!)
~~~
Okay, if the answer's Lalaith, I'm going to laugh, but I don't think that would be "a bit tricky".