I kickstarted the habit in June by joining a bike to work team with three women from my office. Between us we cycled or walked 440 km in the month. I fell off once, embarrassingly whilst stationary at a traffic light, and tattooed my knee with road dirt; I also got lost quite a lot.
There are multiple routes to get back to our place from the city, but however you choose to do it, you're going to have to get up a big hill. In the course of the summer, I tried several routes, some more intentionally than others. It turns out that following the Limmat west is easy and pleasant, so long as you don't mind pushing the bike virtually straight upwards at the end. There's a broad gravel track next to the water, frequented by joggers and families and cheerful dog-walkers, the air smells of riverwater and flowers, and it's a peaceful end to the day. Unfortunately, riding on that gravel with the 14" wheels of my foldable bike was a juddery nightmare and, in my head at least, a near-death experience. I decided to get a full-sized bike. (A new bike, new cats, and licorice or ice cream nearly every day: this has been the summer I've dreamed of since I was ten!) There was a short but scary period of adjustment to the bigger frame and wheels, but having hydraulic brakes and 24 gears is a luxury, and I feel confident now. I've been experimenting with the mobile app RunKeeper to track how far I ride, and how far off course I go, but I haven't played with the data yet so can't give a proper assessment.
Cycling to work has the obvious advantages of adding exercise to my day and saving money on tram fare, as well as getting a better sense of Zürich's geography. Taking the tram to work has the advantage of speed and being able to listen to Welcome to Night Vale, so I won't rule it out altogether, but if I could get my mornings better organised, I would probably be able to. In winter it will be too cold/icy/snowy to cycle for at least a few weeks, so I should get the miles in while I can.