Start out with a training routine that you can live with, one that can work with your daily schedule. I always recommend either working out before or after work, with ever is the easiest. Some of us are morning people, and the other's of us... well we don't wake up till about the third cup of coffee. Either morning or evening is fine, just as long as you stick to it.
Begin with at least a three day workout, work at least two of your major muscle groups a day and start a sensible diet. Try to keep your workouts no longer than about an hour and half. Drink pleanty of water a day, it keeps you hydrated and great for your skin and helps to flush fats out of your system. About a gallon a day would be ideal. This should get your best foot forward and help you on the path to achieve your fitness goals.