Factors to consider during regession testing

I read an interesting material on regression testing here.

Few important point regarding regression testing on which we should focus is as follows:

• Test fixed bugs promptly. The programmer might have handled the symptoms but not have gotten to the underlying cause.
• Watch for side effects of fixes. The bug itself might be fixed but the fix might create other bugs.
• Write a regression test for each bug fixed.
• If two or more tests are similar, determine which is less effective and get rid of it.
• Identify tests that the program consistently passes and archive them.
• Focus on functional issues, not those related to design.
• Make changes (small and large) to data and find any resulting corruption.
• Trace the effects of the changes on program memory.