If the only study guide was the Transcender test, then the teacher isn't a very good one.
As mentioned in another post, checking the CompTIA site for the actual Network+ objectives is a good start.
At that point you need to check several Network+ books to get an idea of both theory and application. This can get expensive if you BUY the most current books. But if you pick up the prior generation books at remainder sales and yard sales, you can get eighty plus percent of what you need.
Many of those books have what they consider to be 'sample' tests in them. Study the tests AND learn why the answers provided are either correct or wrong.
As you go along, PRACTICE what you're learning if possible. You need to internalize things so that you don't have to refer to the book or your notes when asked how you do something or what happens when you do something.
Then find as many different Network+ 'sample' tests as you can and go through them multiple times. That will familiarize you with what might be on the real test and tell you where your weaknesses might be.
When I took the Network+ test, I decided that I was ready when I could get 100% on all the test questions MeasureUp had available on the subject. While the CompTIA test had about seventy questions, MeaureUp had about two hundred. I got to the point that I could do all the questions in forty five minutes.
I also passed the test the first time around.
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