One important thing to remember when setting your fitness goals is that they need to be difficult to reach, but not so difficult that you never get there. It may sound easy but it can be tough finding the right balance. If you find yourself always surpassing the immediate goal infront of you then you should raise your expectations. By not doing so, your body will feel gratified when reaching the goal and not push harder. Remember you are involved in fitness to get into better shape and you cannot do this by not pushing your physical limits.
To get started try tracking your progress throughout the first couple of weeks of your new workout routine. Once you see what your body can handle you can slightly increase the level of resistance, giving yourself a stretch goal to shoot for. It may take you a few weeks to get there but once you do you will feel like you are really making progress. Remember that the mental process is a huge part of your workout. If you believe you can do something you probably can.
For more ideas on how to set realistic fitness goals you can speak with a local trainer. They are used to working with people new to fitness and can give you some pointers for maximizing your time. They can help you track your progress and let you know what percentage of increasing your body can handle. And remember to speak with your doctor before beginning any new exercise routine and if possible schedule a physical to insure your body is healthy and ready to workout.
Physical fitness should be an important part of your life. You will benefit both physically and mentally from exercising. Setting and reaching your own personal goals will give you the satisfaction you need to continue working hard.