1. Only purchase what you need, when you need it. Don't buy for what you will need 3 months from now or 2 years from now, unless you can really justify the expense.
2. Revisit competitive analysis on the supply vendors you are using. This is especially true if your current vendors are not meeting or exceeding your expectations. Compare other vendors to see if you could see potential savings. However, if you have great vendors in place, don't change from a great vendor to save a few dollars. You'll definitely regret it.
3. Try leaving the lights off for an hour or two in the morning. You may be surprised what you can get accomplished with natural light. This will help reduce your utility spend.
4. Use your additional space wisely. Do you have a bit more space than you are using but hesitate to down size to a smaller office? Rent space out to professionals or freelancers that can work remotely. Charge them a daily, weekly or monthly fee in exchange for a desk, wi-fi, coffee, printer use and potentially using meeting room space if they need to interface with a client or take a call.
5. If you can't figure out ways to save on your own, hire a cost-saving consultant to generate more ideas on ways to save.

I hope the above information is helpful.