Knowing how it feels like to lack motivation, be kind enough to help others get motivated.  Not that you’ll really dig in to their lives and help them with their goals.  Just have them influenced with your positive attitude or mood.  You can write about your success stories and share it with others.  One good way is through a blog where it is easily accessed by people around the world.  In talking with people or having quick discussion with a friend, be positive always.  Especially when giving advices, be in the positive tone so that they may be enlightened or hopeful with their goals or dreams.  Share your ideas that might keep them motivated.
You are blessed if you feel positive and motivated, so share it with others.  Helping others to have motivation will also keep you motivated.  Like with this blog,  I  get new ideas  about motivation.   Writing about motivation, goal setting, success, and  positive things in this blog keeps me a positive person as well.