How to prepare regression test suite

What is Regression Testing?

A regression test suite is a set of test scenarios which are prepared to ensure that application is accurate and working fine after changing the builds with bug fixes for each level of testing i.e Functional Testing, System Testing, AT ,Alpha testing etc.

For each new releases of application, three sets of test suites are executed those are 

1.Regression Test Suite.

2.Release Specific Tests. 

3.Defect Tests(Which is fixed in current build).

For every testers has do every common task that while fixing the defects test it again in order to verify fix is not taking or causing other errors in existing as well new requirements.

Before selecting the test cases for regression test suite below points should be consider first, as

1.Application functionality should works.

2.Defects found have been resolved. 

3.Application functional part will handle with some of negative / destructive behavior.

4.Application more visible to customers

5.Application flow where most of the customers will use.

6.Select repeatable test cases.

After selecting the test cases according to above points need to analyze the test cases one more time in order to verify all the functionality is covered and main flow will work with selected test cases. Once the test cases are finalized need to prioritize the test cases as P1,P2,P3 what are the test cases should execute first in order to cover main functionality of the application which should be as per application flow priority.