Top 20 Practical Testing Tips:

1) Learn to analyze your test results thoroughly. Do not ignore the test result. The final test result may be ‘pass’ or ‘fail’ but troubleshooting the root cause of ‘fail’ will lead you to the solution of the problem. Testers will be respected if they not only log the bugs but also provide solutions.
2) Learn to maximize the test coverage every time you test any application. Though 100 percent test coverage might not be possible still you can always try to reach near it.
3) To ensure maximum test coverage break your application under test (AUT) into smaller functional modules. Write test cases on such individual unit modules. Also if possible break these modules into smaller parts.
4) While writing test cases, write test cases for intended functionality first i.e. for valid conditions according to requirements. Then write test cases for invalid conditions. This will cover expected as well unexpected behavior of application under test.
5) Think positive. Start testing the application by intend of finding bugs/errors. Don’t think beforehand that there will not be any bugs in the application. If you test the application by intention of finding bugs you will definitely succeed to find those subtle bugs also.
6) Write your test cases in requirement analysis and design phase itself. This way you can ensure all the requirements are testable.
7) Make your test cases available to developers prior to coding. Don’t keep your test cases with you waiting to get final application release for testing, thinking that you can log more bugs. Let developers analyze your test cases thoroughly to develop quality application. This will also save the re-work time.
8) If possible identify and group your test cases for regression testing. This will ensure quick and effective manual regression testing.
9) Applications requiring critical response time should be thoroughly tested for performance. Performance testing is the critical part of many applications. In manual testing this is mostly ignored part by testers due to lack of required performance testing large data volume. Find out ways to test your application for performance. If not possible to create test data manually then write some basic scripts to create test data for performance test or ask developers to write one for you.
10) Programmers should not test their own code. Basic unit testing of developed application should be enough for developers to release the application for testers. But testers should not force developers to release the product for testing. Let them take their own time. Everyone from lead to manger know when the module/update is released for testing and they can estimate the testing time accordingly. This is a typical situation in agile project environment.
11) Go beyond requirement testing. Test application for what it is not supposed to do.
12) While doing regression testing use previous bug graph (Bug graph - number of bugs found against time for different modules). This module-wise bug graph can be useful to predict the most probable bug part of the application.
13) Note down the new terms, concepts you learn while testing. Keep a text file open while testing an application. Note down the testing progress, observations in it. Use these notepad observations while preparing final test release report. This good habit will help you to provide the complete unambiguous test report and release details.
14) Many times testers or developers make changes in code base for application under test. This is required step in development or testing environment to avoid execution of live transaction processing. Note down all such code changes done for testing purpose and at the time of final release make sure you have removed all these changes from final client side deployment file resources.
15) Keep developers away from test environment. This is required step to detect any configuration changes missing in release or deployment document. Some times developers do some system or application configuration changes but forget to mention those in deployment steps. If developers don’t have access to testing environment they will not do any such changes accidentally on test environment and these missing things can be captured at the right place.
16) It’s a good practice to involve testers right from software requirement and design phase. These way testers can get knowledge of application dependability resulting in detailed test coverage. If you are not being asked to be part of this development cycle then make request to your lead or manager to involve your testing team in all decision making processes or meetings.
17) Testing teams should share best testing practices, experience with other teams in their organization.
18) Increase your conversation with developers to know more about the product. Whenever possible make face-to-face communication for resolving disputes quickly and to avoid any misunderstandings. But also when you understand the requirement or resolve any dispute - make sure to communicate the same over written communication ways like emails. Do not keep any thing verbal.
19) Don’t run out of time to do high priority testing tasks. Prioritize your testing work from high to low priority and plan your work accordingly. Analyze all associated risks to prioritize your work.
20) Write clear, descriptive, unambiguous bug report. Do not only provide the bug symptoms but also provide the effect of the bug and all possible solutions.