The #1 cause of budget over runs is rushing to the design phase before completing due research and analysis. This is like a doctor rushing a patient to surgery before without a proper diagnosis. An out-of-control project is stressful, massively expensive and unnecessary. The solution is successful early planning.
As a part of our DesignAwareness initiative in which we provide open-source content, we created the Instant Project Planning Pack for upcoming projects, that will help you plan in advance and be prepared for your project.