Hey, this reads more like an engraved stone block rather than a crate. I think that you need to ask yourself what are your crate's materials and choose colors accordingly. Also choose a light source and apply highlights/shadows based on that to make it less flat. Finally choose a perspective so you can add volume to your crate. Full frontal/side view with no depth is strange and hard to read, I've only ever used it as part of an animation, but not on static graphics. There is always a way to add at least a hint of volume in any direction. Thanks for sharing.
Dithering works best in small amounts. When it covers a large area, it creates texture, which is unwanted in most cases. Large areas of dithering are common on older art, from when CRT monitors were the norm, because CRT monitors would blur it all together, forming essentially "solid" colours without texture. On newer monitors, that is not the case - dithering looks like texture because each pixel is clear and not blurred.
Using dithering in small areas works because the texture isn't as obvious, it reads more like a smooth transition. Dithering also works when you want that sort of texture. However, for a crate, that's usually not appropriate. For a small image like this, there's usually no need to use dithering for transitions because each colour area is small enough not to need smoothing - especially for something like a crate, where the surface should be flat anyway.
Thanks for the feedback, is there a tetorial or a piece, where I can see how it will be made.