A life without purpose is like a ship without a rudder. The purpose of a goal is to focus your attention. Your mind will reach toward achievement only when it has a goal. There is no achievement without goals.
Establish a goal worth working for. Your goal will keep you going in tough times.
Always have something ahead of you. Continuously visualize your next step. Keep moving after you achieve your goal and set another. Momentum is maintained by always having something to look forward to. Constantly give yourself something to work for.
Do what you can do well, and do well whatever you can do. You can plant your dream.