Areas of the home such as attics, garages, closets and other storage areas tend not to get seen every day. It is good to get in there approximately once a year to dust off those areas where most of your things are stored in the house.
In general, it is a good idea to go through items in various boxes and decide an overall strategy of keeping them, throwing them away, selling them, or giving away to charity. A good organization tip is labelling all the boxes with the items that are inside. This helps you when you need to retrieve items like holiday ornaments.
It is also a good practice to vacuum and dust off various boxes and shelving to keep things relatively clean. Here is a good conceptual concept video from Howcast.