Learn to keep working on your dream. Even if you feel desperate about achieving them.
We usually see only the achievement, not the work behind it. All the sacrifice and long hours that has been put into that achievement. Too many people think that it was easy. Some even dare to talk about luck.
Those who work on their dream can understand what has been invested into achieving anything great.
Be happy for the success of others. They show you that you can do it too.