Become familiar with the lay of the land - or the office space you are cleaning. Ensure you figure out the fastest yet most effective way to cover the floor taking note of any obstacles in the way. If it is a regular gig you'll be manoeuvring around the room like a pro.
Maintain a steady cleaning schedule to prevent the extra overload. This is probably an obvious one but regularly keep on top of high traffic areas is extremely important for efficiency. It's like skipping lunch or dinner, if you snack and eat your regular meals in moderation you become less hungry and maintain your energy throughout the day. If you miss eating during the day you reach the point of starvation and you binge on whatever is around and usually grab that midnight snack which we all know doesn't help in the long run...
Assess each room/area individually - by maintaining a rigorous cleaning schedule, you can minimize the time spent by cleaning low traffic areas less frequently. Example; the meeting rooms with the plush carpet that get used once in a blue moon may need a deep cleaning every few months compared to that of the hallways of an office building with low-pile carpet in may need a deep clean every few weeks. If you were to clean all the carpet areas with the same schedule it wouldn't be beneficial and could even create a negative impact on the life of the less durable carpet.
Ensure you have the right cleaning sized machines and sufficient amount of cleaning supplies for the job at hand - also ensuring it all fits within your budget.
Speaking of cleaning equipment and supplies - another effective way of improving cleaning times is by investing in the correct gear. You could clean a lot faster and more efficiently by doing less if you had the right type of chemicals and or equipment for the job at hand.