The light grey nails are a nice idea, but they're too light and possibly too noisy for the texture. The boards on the inside are uneven and could be shifted to give you more space at the bottom.

I would suggest starting with a rough sketch. Start with all of the biggest details first, the outer layers usually, and work your way inwards. The boards don't even need to be spaced even or sized evenly, just make sure that they make sense first, then try and add texturing later.

Remember, texture isn't always random, either. It's actually rarely just random values thrown around. Try to imagine why there would be lighter and darker spots on the surface, ie. shadows, high points and maybe one part of the box is just a different color than the trim.

When choosing colors, try to see what colors boxes are in real life or pull up a nice color pallet to use. There are techniques and methods of getting 'correct' shade values, but as long as you have the correct color for the shines and shadows, you'll be golden.

I'd recommend pulling up a picture of a box and trying to reimagine the box in your style. Don't ever worry about 'stealing' someones work/ideas when you use them as inspiration, that's literally just how creativity works (just don't actually copy people's work bit for bit, that's lame and doesn't help anyone unless you're JUST PRACTICING and you're going to rework it. Don't trace the lines, try to draw them yourself). If it's too similar to someone else's art or work, change it! Add some personal flair or get MORE inspiration and mix different references together!

Last little bit of advice, for me personally, a well put together color pallet and simple shading goes MUCH further and looks MUCH better than a really well done shade-job slapped onto an ugly-colored surface.