I would consider three areas/types of "waste" or "conservation opportunity" within an office environment: 1) things that are placed in waste streams whether they be a landfill, recycling, or other disposal stream 2) excessive use of resources whether it be an "oops" at the printer/copier, energy for heating and cooling, or the lack of low flow toilets, or the incomplete use of items 3) looking for alternatives to practices, policies, processes, supplies, and the more for resource saving, complete use, reuse, and repurposing opportunities.
Packaging remains an issue in the office as well as for the retail store consumer. Some packaging is most recyclable, others is most interesting, and others can simply be considered as simply excess waste. An office has control of its own processes and products. An office may have some purchasing options and/or a voice with its suppliers. And, an office certainly has some options for where and how it disposes of its packaging. Like the partially used office supplies, you may even find some folks out there who would love to be given your used packaging donated to them. Increasingly, there are businesses popping up who will take away your packing peanuts, and all sorts of other packaging for re-use or remanufacture.
Paper is an issue in an office. Complete use of paper and recycling is of course an obvious opportunity. But, following the paper's flow through its life cycle within the office is likely to uncover much more conservation, complete use, and recycling opportunity. This is likely to require procedural changes and may even require some investment for something like an internal, electronic signature/approval or editing/revision process. In some cases, it may be as simple as changing the type of paper used.
Another whole area of waste in the business/office enviornment is related to utilities. In some cases, things as simple as a change in wall paint, different window dressings inside (i.e. window blinds or even box valances) and outside (i.e. exterior blinds and shutters, awingings), and landscaping from vegetation to hardscapes can reap benefits. Lighting and water use are often cited. But, dress code or culture, the existance of a couple of extra coat/jacket trees, and these types of things can also enable a change in the building thermostat too. Oddly enough, protected entry ways, window caulking, door seals and the like are often less than ideal in many office places too.