I cut out a section of the sunset minus the land. The land will be in it's own layer

The land is separate because I wanted to change the horizon. The bottom of the sunset was a lot more washed out than I cared for and I knew I would need space for water as well.

I duplicated both land and sky then flipped vertical and moved it into position. The water effect is created by using a somewhat specialized displacement map.

To create the displacement map, create a new project of 400px square, fill black or white, but not transparent.

Add 400% noise, gaussian, monochromatic.

Using Free Transform>Perspective, widen the bottom to 250% or so, it doesn't have to be exact. Now crop the image back to 400px square and then repeat the process twice more.

Now go into the channels tab and select the red channel. Choose emboss 10px with the light angle set to 90 degrees.

Repeat this for the green channel, but this time with the light angle set to 0

Save as displacement map.

Now return to your original project and apply the displacement map to the lower sunset layer.

Mask out the flowers. Duplicate them a few times and scale the copies to different sizes and overlap with the original to fill the spaces. Now merge these layers and flip horizontal to build on the line of flowers so that you can have some variety. Apply a layer mask to blend the 2 flower groups into one.

Now you will want to make some color adjustments. To be perfectly honest, I simply eyeballed it against the sunset so I cant give exact settings here but I can tell you that I mostly increased the reds and to a lesser extent the yellows. I kept playing with it until I was happy with the color. This layer also got a crosshatch filter to give it a smoother look

I added a pattern fill layer of linen and set the blending mode to color with a fill of 40%.

Added a color adjustment layer set to soft light blend, 75% opacity. The color is #f2a809