CLARKE 

I started by erasing the bottom of the picture to get rid of the harsh line.

Press save when done. Then I cropped part of the picture using the 16:9 option

You don't have to press save when you cropped the picture. Just close press the X (located on the top left) when you're done. 

Keep opening the saved picture and repeat the cropped process. Try not to go overboard with this. 

Then add the cropped pictures and adjust the size

OCTAVIA

I was inspired by @bloodflood 's book cover, Athena. 

Screenshot this picture

Then add the photo above and tap Screen.

Then add the photo above and press Multiply. Erase the harsh edges and add some more trees.

Let me know if you have any questions!