The default setting for layers in Photoshop is to show them to the document bounds. This means your little preview shows where they are on the document and that's very tiny! to better be able to see what you are working with on each layer, change this one simple thing.
Go the layers palette and right-click ON the thumbnail preview. Click on the option to "Clip thumbnails to the Layer Bounds"
Now, your layers actually show the elements! Nice!