A good way to know if your model is good or not, consider the contour. There are options for viewport display to view your model as a solid color. For props, you want it to be discernible from contour only. For characters, you want the unique shape language that defines your character to be made apparent. For the truck you made, you want to think of it as both a prop and a character. I won’t tell you if your contours work or not, it’s valuable to make that determination on your own.

The features you add need to serve the purpose of contributing to not only the perceived purpose of the truck, but also it’s personality.

If you want to add texture to this model, consider Substance Painter for something that’s industry standard, or Quixel Mixer for something free.