It's not bad but definitely needs some more "umph!"
Try looking up some hard-surface modeling techniques and some texture baking tutorials.
Grant Warwick does some good videos on hard surface modeling and just google "Render to texture" and how to bake textures.
Basically what this does is you make a high poly version of your box with some nice details then you bake the high poly onto your low poly, retaining the low poly count and still gaining all the details of the high poly model.
You can also use render to texture for a number of different things such as making spec and alpha maps. Adding these to your model instead of just a diffuse will greatly improve the quality.
Good advice from Jpeppa, pretty much somes up your next steps you need to take.
Take this with a pinch of salt, but at my university we had a lecture from Teagan Morrison - an environment artist (lead?) from Naughty Dog - and he mentioned that Texture artists are currently a dying breed in the industry. He mentioned how Naughty Dog, and most other companies, are no longer hiring people for the sole purpose of texturing and the industry now expects Environment, Character and Mechanical artists to texture their own models. Its definitely worth keeping in mind and making sure you're comfortable doing the entire workflow which you may well be, in which case you can ignore this
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Did you hand paint that?
It's not bad but definitely needs some more "umph!"
Try looking up some hard-surface modeling techniques and some texture baking tutorials.
Grant Warwick does some good videos on hard surface modeling and just google "Render to texture" and how to bake textures.
Basically what this does is you make a high poly version of your box with some nice details then you bake the high poly onto your low poly, retaining the low poly count and still gaining all the details of the high poly model.
You can also use render to texture for a number of different things such as making spec and alpha maps. Adding these to your model instead of just a diffuse will greatly improve the quality.
I hope that helps and gives you a good start!
Take this with a pinch of salt, but at my university we had a lecture from Teagan Morrison - an environment artist (lead?) from Naughty Dog - and he mentioned that Texture artists are currently a dying breed in the industry. He mentioned how Naughty Dog, and most other companies, are no longer hiring people for the sole purpose of texturing and the industry now expects Environment, Character and Mechanical artists to texture their own models. Its definitely worth keeping in mind and making sure you're comfortable doing the entire workflow which you may well be, in which case you can ignore this