The work of Bob Green and Oprah has helped me a lot in understanding how to breakthrough plateaus. One of the reasons exercise is so important for people like myself is that it immediately effects insulin resistance (according to Kaiser in their pre diabetes class.)
Start slow. In the beginning I just did 15 minutes of easy aerobics three times a week. I would walk just ten minutes. Five minutes out and five minutes back. Where I live the hills are considerable.
Success with my weightloss has always coincided with a (courageous!) addition of either difficulty or time onto my workouts.
I workout twice a day about 5 times a week.
I do cardio in the morning when I wake up. I cross train. I do hike, use my Kathy Smith video's, I do step aerobics too. At least twenty minutes in my target heart range. Stretch after a five minute warm up and stretch in your cool down too. This helps prevent some of the post workout stiffness that can happen. When I hike I do 1 to 2.5 miles. I have an iPod that I wear in an arm band. I wear sunglasses and sunscreen. I carry a baton for self protection and my cel phone.
I do yoga in the evening before bed. This is the most important part. I use the Yoga Today video podcast on iTunes. I started at just being able to do 2 minutes. I have worked up to 40 minutes. The first time I did it I did not believe it would work at all. I thought it was bogus. The next morning I had lost four pounds over night. This does not happen consistently however I do believe that it makes a big difference. I heard that yoga puts you into fat burning mode immediately. I don't know why it does this, but it does seem to work.