Park further away from the door
Parking further away from the door will afford you a few hundred more steps both to and from your office. Also, it puts your vehicle closer to the exit at the end of the day so you don't have to fight traffic in the parking lot.
Walk more briskly
Take your pace up a notch. Moving just a little bit faster when walking to and from your vehicle at the start of the day, to and from lunch, and at the end of the day will raise your heart rate and give you a little bit of cardio.
Take the stairs
Unless you are pushing a cart or carrying a large load... TAKE THE STAIRS! :) You will get in more steps, give your legs a nice little workout and it raises your heart rate just a little... once again, all good things for your health.
Walk away from your desk
If you tend to sit behind a desk all day... don't! Set a time for 20, 30, or 40 minutes and when it goes off, leave your desk for a minute or two. Walk down the hall, visit the bathroom, go to the fountain for a drink or refill your water jug. Anything to get up and move around even for just a minute or two. Besides, there is good evidence that you will do better work when you step away from the desk every 20-40 minutes.
I love this one. If you have a one-to-one meeting with someone and you know it is going to last 10-15 minutes (and you don't need to be at a table or meeting room) go for a walk. This is especially helpful when you are trying to hash out solutions or generate ideas. For some reason motions gets the mind gears working as well so not only will you get more steps in but it may actually prove to be a more effective meeting.