There are many steps in the process to become a commercial pilot, and one of the final steps is a written test that will exhibit that pilot's training and experience. A practical test may also be included, which means the pilot will have to safely operate an aircraft and be examined doing so. In order to prepare for a commercial pilot test, you will first need to earn your private pilot's license, and pass medical clearances that show you are in good health to fly. From there, you can enroll in preparation courses that will help you prepare for your commercial pilot test.
First and foremost, you will need to do some research into the rules and regulations regarding commercial pilot licensure in your country or region. The rules can vary significantly, and while you may need to take one specific commercial pilot test in one country, you may need to take a completely different test in another country. In the United States, the rules for licensing commercial pilots are outlined by the Federal Aviation Administration (FAA). You can check the FAA website to figure out what steps you need to take to prepare for a commercial pilot test.
Many of the topics covered on the commercial pilot test will be similar to the topics you learned when you earned your private pilot license. If you have study manuals or other literature from when you earned your private pilot license, you may want to go back and review them to ensure you are refreshed on the basics. You will also need to do some studying into various topics that were not previously covered; it is a good idea to take a course that is approved by the FAA or other governing body in your region. Such courses will cover many of the topics that will be present on the commercial pilot test, and you will likely be given training manuals or other materials that will prepare you for the test.
If at all possible, talk to a current commercial pilot who can lend you some insight as to how to prepare for the commercial pilot test. You will not know what specific questions will be on the test, but the commercial pilot may be able to give you some tips and strategies for passing the exam. You may also have access to practice tests online, so be sure to check the Internet for various practice resources.