The Ten Principles of Good Software Testing

Testing principle 1: Business risk can be reduced by finding defects.
Testing principle 2: Positive and negative testing contribute to risk reduction.
Testing principle 3: Static and execution testing contribute to risk reduction.
Testing principle 4: Automated test tools can contribute to risk reduction.
Testing principle 5: Make the highest risks the first testing priority.
Testing principle 6: Make the most frequent business activities (the 80/20 rule) the second testing priority.
Testing principle 7: Statistical analyses of defect arrival patterns and other defect characteristics are a very effective way to forecast testing completion.
Testing principle 8: Test the system the way customers will use it.
Testing principle 9: Assume the defects are the result of process and not personality.
Testing principle 10: Testing for defects is an investment as well as a cost.