The private student I’m teaching today studies English for the TOEFL. The TOEFL she is getting prepared for is not the internet based, but that of two generations ago: ITP (Institutional program also known as paper-based test). Since the score she needs is not like 600 (which can be an equivalent of 100 in the iBT), there is only one thing she should do. That is to learn all the basic rules for the “structure and written expressions” section. Simply put, she should learn basic grammar. There are only limited numbers of rules that are tested in this section, so by focusing on them and practicing them repeatedly, the required score can be achieved.
This is what the average Japanese test takers used to do back in the 60’s up to 90’s (and for some people, still now in the 21st century). They were criticized for the lack of speaking ability, which was then added to the exam.
This is how tests evolve. Once thought of as satisfactory, the test gradually looks quaint and malfunctioning. This is modified by adding and subtracting items. As far as the TOEFL is concerned, grammar has been removed from the test, while the passage (both reading and listening) has become twice as long, and the speaking and the writing sections have been added. With 4 hours 30 minutes to complete, obviously, the current test looks and is more difficult.
This way of evolution may apply to other tests. You may find a certain test rather simple and easy to pass, but you never know, by the time your child take the same exam, it will have become one of the hardest. Then it’s time you show off your certificate (which you got a generation ago).