Guide for Resource Efficiency (PMBOK Seventh Edition)

Introduction:
Resource Efficiency refers to the optimal use of a project's resources, those being materials, energy, and human resources. It is important because efficient use can greatly reduce cost, improve project lifecycle, and minimize the environmental impact.

Resource efficiency involves strategies such as just-in-time delivery for materials, energy-saving technologies, and efficient human resources management.
How it works:
Implementation of resource efficiency starts with a thorough analysis of your resources, understanding their current usage and working out the methods to minimize waste and maximize utilization. This is followed by continuous tracking and optimization.

Exam Questions and Tips:
Questions on this topic generally check your understanding of how resource efficiency can be improved and methods to track it. Below are some tips:
1. Understand the difference between resources and put emphasis on types that are more crucial to the project.
2. Understand the benefits of efficient resource management. These could be direct cost savings, improved sustainability, or better project timelines.
3. Know about tools and techniques to measure resource efficiency. They may include various project management software or methodologies such as Lean.
4. Note that practical examples always help. Use instances from your experience or from case studies discussed during the course.
5. Be mindful of the logical dimensions of the questions. Sometimes answers might not be straightforward. You may have to consider trade-offs between resources.

In Conclusion, being efficient with resources not only saves money but also contributes to sustainability, ultimately leading to a successful project delivery, a skill highly sought after in PMP certification.