How can I make these accessories look more believeable?
Obviously they aren't but is there a way to make them look so they are not that fake?
I tried using a drop shadow but that only helped a little.
I have other images where I need to add jewelry to real models so it would help to learn how to do this.
The direction of the Drop Shadow is important.
And sometimes a simple Drop Shadow is just not good enough because the structure being shadowed by an object may be much more complex than a flat surface.
In this case I would recommend to
• adjust the color of the objects with the appropriate Adjustment Layers to fit better into the background image,
• clip individual strands of hair from the background (or paint some) to partially overlap the edges of the objects and
• in the case of the hat to create fake shadows and lights (on separate Clipping Masked Layers) to simulate the lighting of the background image.
Just add a black Solid Color Layer above the Layer with the hat, fill its Layer Mask with black, use Layer > Create Clipping Mask and then paint in a light shadow on the left side.
Instead of a Solid Color Layer Curves, Levels or other Adjustment Layers can also be used.