Motivation is important to achieve anything. Staying motivated becomes a challenge when you are eager to see results but the process seems to take longer. There are many ways to keep up the motivation.
Form a group to workout with or at least a partner. This will help maintain motivation. Another way to keep motivated is by keeping a log of body measurements and your diet to see how your body is responding to exercise. Always weigh yourself on the same scale to avoid errors. Also remember that you will weight will not go on a steady downward trajectory. It will move a little up and then down but on an average it will head down if you stick to your routine.
After you do your exercises, flex your muscles and see the changes. Take periodic photographs in your favorite T-shirt and see the changes. These are some of the ways to stay motivated.