Hm is it scaled at all? There are pieces at double size, you can definitely fix that.
You don't need any techniques to make it more realistic, just simple things. Techniques are for polishing.
Are you using a reference? If not, find one and please link to it.
Contrast can be used to an extent, and level of detail, to separate the layers (lowest have low detail and low contrast, perhaps even hueshifted towards blue)
Simple assessment of what you're trying to portray. Working off your ref, think logically: what does this section of pixels represent? Could it be done better or differently? Does it add information (good) or does it only add noise (bad)?