How to improve your photo
Details. I still struggle with details when dealing with exposure, focus and composition, but it's easy to find fault later. This photo is about the couple's engagement, so the four subjects of the photo are the two faces, the ring and the relationship of those three items. Lose the clunky bracelet - it completely eats up the ring, rendering it almost invisible. Bring it all in tighter - the two faces and the ring. Work the hair - remove the strands of hair over the flower, control the loose hair on below her neck. It's easier to do it before you shoot rather than having to clean it up in Photoshop.
Get your subjects comfortable. It could be argued that they're also engaged to the camera. Try to direct their energy toward each other a little and forget the camera. A slight head tilt, a little snuggle. If you can accomplish that, you'll get a less stiff, warmer, more natural photo.
A little hair light, a slight softening and/or vignette would make this photo pop. You're 95% there, attention to the details would make this picture sing like angels.