This is the first ever Lúthien picture which I can say it is somewhat her. You almost made it, but still missing the Elvish grace of her. She is graceful for human, and really beautiful, but Tinúviel was the Most Beautiful of the Fairests and this unsuprpassability you can't managed. But even this way, this is the most Lúthienesque Lúthien I've ever seen. The eyes are there and perhaps the nose.
Sorry, I am maximalist.
And meanwhile I have the answer to my question I made in my previous comment. Elen síla lúmenn omentielvo, mellon nín!
This is my Luthien. I love her eyes - so alive and young. I love how you've also blended her hair (so perfect!) with the background, as she if she just rose from nothing and appeared like a beautiful apparition... which I imagine is how she appeared to Beren the first time he saw her.