Whether you are preparing to get your Class A (CDL) License for the first time, or you just want to add endorsements on your license, you need to set aside time to read for the test.
In my experience, I have realized that when one dedicates more time to practicing the tests (after reading the book), he/she shouldn’t have problems passing the test. This is because in dedicating enough time to practicing the test, you will familiarize yourself with the questions and also work on eliminating the fear of taking the test.
The links below are links I have personally used to help me practice for my CDL tests and be able to pass them on the first try. When you go to these sites, try to see if you can find tests that are specific to your state. Some sites offer state specific tests while others offer a general test.
Either way, practice as many questions as possible. Obviously, the more questions you practice, the more chances you will pass at the first try.