I've tried to do one of these half-submerged water edits many, many times, and I could never figure it out. I want to share what I learned with this edit because it seems a common sentiment that this concept is a little complicated. Hopefully, this info will help if you want to do an edit like this!
I painted the water with a color mask. I filled the whole canvas with medium green, lowered the opacity to about 60%, and erased where Amelia's body would peak through the water. I made the edges irregular to mimic how water pools. I used a hard brush, you want a lined edge, not a soft one. I recommend using a layer mask but you could do it with a regular layer.
The biggest concept I had to work with for this edit was depth. The highest points of Amelia's body would be about the water, but what about the deepest? I filled my canvas again with a darker green and shaded in parts where the water would be deeper; like the bend of her elbow and between her thighs. I recommend erasing with a soft brush.
Next, I outlined the edges of her whole body with a soft brush in the background color to blend Amelia's body into the pool of water. This helped her look more submerged.
This really helps it look like water: Where the body pools on top of her skin like around her armpits and on top of her belly ... I erased along the edges of my first green layer with a brush on ~35% opacity. I didn't want to erase it all but give the impression the water was thinner and more transparent.
I outlined the water on Amelia's body with a dark brown color, about 2px, on multiply, to help make the water look like it's rolling onto her body. If you go over onto the water later, don't worry it actually helps the effect.
After these steps, I continued to tweak things until I liked them. I added more shadows and some highlights.
I placed the lily pads next and added a small drop shadow under them so they looked like they were sitting on top of the water.
This step was my favorite part; I used a 1px white hard brush on 100% and drew different-sized lines along the edges of the water to create small reflections. I did it around some of the lilypads as well. This helps the water look more like water.
That is about all, I drew hair and added petals and bugs, then color grade the picture. The colorgrading really brought this picture to life!
I hope this helps anyone trying to create this kind of edit! I am always available if you have questions or if there is something I can help you with!
