Follow the Lean Way. Start small & iterate. Make small changes quickly and often. Establish a continuous improvement loop. Make decisions purposefully based on experiments. Design to data, observations, surveys, piloting, focus groups, interviews are the ways to validate any hypothesis. Note that each method has its strengths and pitfalls. Whatever the changes are, they must be functional and serve a purpose.
Be flexible. Workspaces should be designed appropriately based on that fact that working environments and people are dynamic in nature. It should fit varying sizes of people (small and big) people. Consider Lego-like furniture where furniture can be set up in many different ways to suit different contexts, situations and people. If people are away from the office, the unused space can be used for other purposes if furniture are easy to dismantle or move aside.
Improve accessibility. Reduce time taken for an employee to move from one place to another. Meeting rooms, quiet areas, dining halls, outdoor space, etc should be within distance to each other. Since these are generic spaces (does not require specialized equipment and design = $$$), make lots of them. Set up neighbourhoods and each one of them should have a few of such generic spaces. Have lots of informal meeting spaces around neighbourhoods for impromptu meetings. Remove the friction for people to interact. Utilize portable technology to make presentations or discussion mobile.
Personalize workspaces. Design locally. Design to the economics of the situation.
Sit team members together. Team members should sit together instead of having members of different teams to sit together. It is great to get people to interact in order to drive innovation but instead of them sitting awkwardly together, have common spaces where people hang out will be great places for people to bump into each other. Draw them together through food or leisure activities. Another option is to co-locate some people to sit with another team for a day.
Noise vs Quiet. Provide choice for employees. Have lots of rooms for buzz sessions. Rooms that accommodate various group sizes. Note that a study has shown that with high partitions, a person tend to communicate in a louder manner compared to when they have eye to eye contact. With eye to eye contact, they tend to monitor their own volume more.
Ping pong over pool due to surface issues.
Prepare for scaling. Is what we are doing currently setting precedent? Is what we are doing will scale well? Design (with a focus on scaling) also depends on the nature of your business. Create temporary space if lack of space in the short term.
Focus on environmental variables. Research on how various aspects of environment affects the employees. Indoor Environment Quality (IEQ) metrics such as acoustics, thermal comfort, lighting, biophilia elements.
Focus on business outcomes. Experiments and decisions should focus on business outcomes. What drives productivity? What promotes well-being? What drives collaboration?
Involve people who will be vocal about giving feedback. They should be the one driving the decisions.
Innovate when space is limited.
Allow naps. It should be a part of work. Be open and not be ashamed of it. Some employees might be hesitant with this arrangement due to cultural reasons.
Design for maximum capacity. Put enough conference rooms for 50 people instead of for the numbers you have now.
Design for people. Do not design for technology. Technology moves rapidly. It becomes obsolete fast.