Once you have created your Risk Register and are ready to begin planning your tests, a good place to start is to build a "Test Strategy" first. The Test Strategy helps you to look at the "Big Picture", and think about the type of tests that you will need to run without worrying about any test detail.
For example, will you only need to perform functional tests, or will you also need to look at application performance? What about Security, Usability and Data Integrity tests? If your software is to be distributed, what about installation / platform / upgrade testing? Will all types of tests (i.e. Functional, Performance etc) be run intermixed, or should you complete functional testing (or some other type of test) first, then move on to other types of tests?
Test Lead provides checklists and examples to help make sure you have considered these and other types of questions. The "Demo1" project supplied with Test Lead contains a detailed example of a Test Strategy to help you set up your first strategy document.
A Test Strategy is a document that can usually be easily understood by someone who has business knowledge and skills, but does not have a background in software development or testing. For this reason it can be a very useful aid in defining the magnitude of the testing effort, explaining this to someone else, and in obtaining an appropriate testing budget.