First, I have to say congratulations, because this piece doesn’t seem have any real mistake I can see. This would already be a rather good asset to be used in a production. So, everything I am going to say is going to be ways of going a step further rather than pointing out mistakes.
The first thing you could improve is presentation. Some of the metal parts look flat and gray, because they have nothing to reflect. You could use an HDRI to create better reflections or put the model into a scene if you have one.
Then, if you want to improve on the model itself, I would tell you to look at blending between multiple textures on the same material. Looking at the image, you seem to have used seamless textures for everything. While this works, there are ways to create more variations and push the texturing further.
If you plug 2 different textures into a mixRGB node, you can then create a mask that you paint by hand and use that as the factor, allowing you to decide where each texture appears on the model. Or, with the same principle, you could also use a mix shader and blend between 2 entire materials simply by painting a black and white mask.
What to do with that technique:
In real life, objects don’t get dirt and wear evenly. Corners and edges get scratched more than the rest. Iron rusts quicker on corners and on areas that get scratched. Dirt accumulates more in cracks and enclosed parts of objects, where it doesn’t get wiped off as easily. In your example, the barrel could have some dirt towards the bottom, where it often gets put on the ground and the scratches would be concentrated around the dangling objects, which rub against it constantly. The metallic objects would have more wear and rust near any sharp edge, because those spots are more likely to hit obstacles, and the parts that actively rub together would become polished and shiny. Maybe the lantern would have soot on its glass, especially near the top, close to where the smoke escapes. The leather belts would crack and peel at the edges and close to the holes (search for images of old leather belts).
Another detail that might be useful is to make the modeling a bit uneven and crooked on purpose. Make the wood planks have slightly different lengths, with very slightly crooked and diagonal tips. The thinner metal objects could have some bent parts and dents, especially the shield, which has probably been hit by weapons. Maybe the handle of the pickaxe is slightly uneven and lumpy, as it has been crafted by hand.
In the end, it all depends on what the story of the object is and how it has been used. And don’t hesitate to look at reference photos.
