Answer:
Get your book out study it thoroughly and take the test. If you dont pass it at least you have an idea of what is on it.
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---While I certainly agree with this answer, it's also important to note that there are a lot of things on the NCCER test for pipe-fitting that you will pretty much never run into in the field. With that, and the above statement, being said, there is a company called Contren that has a learning series for any craft in the NCCER certification series. Here's the link to the pipe-fitter's series in the Related Link below.