Summarize this article:

Exercise should be enjoyable. Gain control of your routine and think about what you want to get out of it. Decide what you want to achieve in the short term, as well as the big picture. Goals will keep you focused on healthy lifestyle change.  Set goals that are S.M.A.R.T: Specific, Measurable, Achievable, Relevant, and Time-bound. For example, "I will run a 5k in two months by walking/jogging/running three times a week."  A short term goal might be to determine if you can do something simple like walk one mile. If not, that is a good, achievable goal.  Long term goals should be something you hope to be able to do after a few months of dedication. Using the mile walk from the previous example, you might consider upping that to a 2 mile trip to the store and back. You might also ask your doctor if your body is capable of building toward running that mile. This simple step has many benefits. First, you ensure that you have a plan for getting enough exercise. Second, it will limit how much you exercise, helping you get back to other important aspects of your life. Scheduling time for exercise and other obligations is part of a healthy life balance. Make a "date" with yourself for exercise. Put it in your calendar just as you would a trip to the dentist. Remember, it's preventive healthcare! This will make it feel like a social appointment with another human being that you need to keep. You will be there to encourage each other to continue the routine after the newness wears off. This will also make it easy for you to monitor each other for early signs of exercise addiction. If your workout buddy becomes dishonest or secretive about their exercise, gets angry if they miss a workout, or is ramping up their workout to non-recreational levels, they may be developing an exercise addiction. You should watch out for any changes like this in yourself as well.

Summary:
Set goals for yourself. Set aside time in your day. Exercise with a friend.