You will almost always have to resort to some guessing. In fact, you can expect to not finish some sections. The test is designed so that only a few can complete it. This does not mean, however, that you can't maximise your chances. You may even be able to complete some sections. The main thing is to be on the go, do not take the time constraints lightly, and do not dwell on a question too long, you can come back to it later if you have time- you've probably heard this time and time again, but I cannot stress this one enough. It's one of the main reasons why I will be taking the test for the third time.
Hope this helps! ^_^
*ETA*
Besides, guessing is also a really good strategy. You can make an educated one.