1.) Find the right treadmill for your space- In my case, I needed something small that could easily be stored away when not in use. After researching many models, I eventually settled on the inMotion 7900 Treadmill for several reasons: (1) The price point (2) Easily stored when not in use (3) Self Powered- I really liked this aspect of the treadmill. I was happy to purchase something that doesn't require regular charging or batteries.
2.) Space Configuration- In my apartment, I already had a permanent desk set up and didn't see the need to remove it since my awesome PC is stored on it (joke). My solution? After spending some time considering my space, I realized that by pushing the treadmill up against the breakfast bar in my apartment, I already had great desk/work space. Also, this is an area of my apartment that is very underused and I was happy to find a new use for it other than junk mail storage.
3.) Get to work- As some other people have noted in their Walking Desk Instructables, the first few days take some patience and getting used to. Day 1 felt a little awkward and I was really happy to get off the treadmill and sit down for lunch. By the end of day 3, I really felt like I had more energy. Placebo effect? Perhaps. But, regardless of the reason, I feel like my posture has improved and that I have more energy. Of course, there are times when I get a little tired. But, as some others have noted, the set-up simply becomes a standing desk which has tremendous benefits unto itself.