Action will enable you to accomplish and achieve. But something must come before taking action: thinking.
Think first. Yes, think big and think bigger, but always think first.
Taking action without thinking will lead to many avoidable mistakes and errors. Taking action without thinking first will lead to unnecessary quarrels and arguments, hurt feelings, and misunderstandings.
Taking action without thinking will lead to wasting much time and energy.
Taking action without thinking might get you far, but it's likely to get you far in the wrong direction.
When you spend time thinking about your options and about consequences, you will be able to learn from each experience to think even better and wiser next time.
([From Rabbi Zelig Pliskin's book: "Taking Action" - pages 40-1] (Artscroll.com)