What helped me lose almost 20 pounds was (1) increasing my steps and (2) measuring my food and logging it faithfully until I reached my goal weight.
Getting the steps in can be hard if you have a desk job, but if you can find a way to get a walk in in the morning before work, one at noon, and then maybe one or more after work, you'll find your step counts going up. I personally like to use the treadmill at the gym three days a week. I read or listen to music or recorded books.
It takes a bit of time, but when I think about stopping, I ask myself, "Well, would I rather be sitting at home getting no steps, or staying here for a few more minutes getting some steps in?"
Another thing some people use is a treadmill desk. I haven't tried it, but I have a Fitbit friend who uses one and says her step counts go way up when she uses it.
I think there is also a group on here, somewhere called, "Desk Workers, Unite", or something like that, and they will probably have lots of good tips for getting your steps in when you sit a lot.
Best of luck and happy stepping!
