Tip #1: Live close to your work or have your work be close to transit.
If there is one thing that you must do to make carfree living possible is that you should live as close to your work as is reasonably possible, or have your home and work be accessible to major transit lines. This may be a stretch with average commutes regularly extending to 30+ miles.
To be honeset, without either, it is almost impossible to function carfree. If this is not possible you may have to consider a new job, telecommuting or some arrangement that makes transit possible. Note it is not uncommon for biking distances to be 10 - 20 miles. It is also best to have a job with a regular schedule and showers if you choose to bike or jog.
Some companies support their own version of transit to make this possible. Google for instance has Wi-Fi enabled buses between San Francisco and the Google campus in Mountain View. Yahoo soon followed suit. Cisco has shuttles between their main campus and the BART on the East bay (Oakland area). This is not limited to the Bay area as some suburban campuses in the Chicago area have shuttles between train stops and the office parks. If your employer does not have such a program, ask. Otherwise they won't know there's demand.