how to improve in Manual software testing

when we gave the quality , easy, and understandable test cases produce to client requirement through manual testing,

Can you elaborate more on what you intend to know. You question is more on the general side and the answer will depend on the tester's skill set and the client/company's QA practices.

On a second visit to this question makes add more to my earlier answer.

As a manual tester, most of the times if not all, is expected to follow an existing test case or test case designed by another tester. To best use your manual testing abilities, follow test case or the test script and use it as a jump off point to play or explore the application.

Don't worry I haven't use Google to answer this question. I'm writing from my own personal experience.

Add this as well:

- When there is an update in an application, make sure you test all data/features that should be modified has been modified and all other data/features have remained unchanged.

- It is impossible to check every piece of data, but occasional quick scans prove valuable in unearthing any corrupted data.

- Work closely with developers when debugging and maintain harmonious and personal relationships with them. This way you not only have good friend, but they are developers who cannot readily dismiss your bugs! some applications may have most of the important things happening behind the opaque UI wall that very little is known to the tester to effectively test the application. In this scenario, developers help is inevitable to deliver a quality application.

- Make sure you ask developers to create testability points or test interface to make sure some of the selected internal show thats ran secretly is available to you. This will greatly help when product hide all the important stuff behind the opaque, thin UI wall. Convince developers that a small amount of test support code will immensely help unearth show-stopper or critical bugs.

- Make sure you check the application doesn't do what isn't supposed to do.

- Design test cases that have maximum detail on expected results and not too rigorously detailed on the steps. This way your test cases can be used by anyone who knows to operate the application and bugs can be effectively found without blindly following the script/test steps. The goal of the test case will be effectively met aside from finding bugs. Win-win for everyone!
- Refrain from designing test cases that only you can understand

- Write bug reports without blaming the developers. Sometimes, it may not be the developer's fault. It may be due to code replicating itself. This way developers will be keen on getting the fixes instead of banishing them. Accurately assess the seriousness of the bug and include it in the bug report from the end user's viewpoint. This will convince everyone that it indeed has higher priority over other bugs.