Photoshop - Learning to use Layer

I worked on three projects for Graphics and Technical Writing this past week.

A recolor of a black and white photo:

Adding the Earth to become the iris of an eye, and shifting it:

 Creating a small (and probably too barren) still-life:

From these assignments, I learned how to effectively use Photoshop layers, as well as the majority of the main tools available. I learned that you can use layers to create some cool effects, such as making it look like the bowl in the still life is actually there (you can kinda see the apple sticking out the top, although it's admittedly rushed and poorly done). You can also use layers to help with things such as alignments, like when I made the closed eye, I made the closed eye image less opaque, so that I could overlay it and then add it to the image.

Overall the layers within Photoshop are very powerful, and vital for knowing how to properly use the software.