I'm going to give you one of those answers that sound like a riddle but it's true.
I have the give credit to NCEES, they make a test like none other. The only way you pass the PM portion is by becoming a super versed in the subject. Abstractly versed.
You also need some great books to look things up, this is key for Geotech, people that say all they used is the Ref Manual weren't taking Geotech.
Get a few Das books.
You can study all you want but if you don't have the "vibe" of how to do things you won't get it.
They do all sorts of tricky wording and little things to throw you off, you have to be solid.
I studied super hard the first time and failed (like over 400 hours)........, the second time I didn't study anything at all and just thought about all the concepts, over and over again, what if this, what if that, and passed the second time after not opening a book for 6 months.
I'm not saying do this but now you have seen the battlefield so remember the style when you study.
It is definitely a journey, as it is intended to be, so try to enjoy it. It will feel great when you complete the mission.
Also selling all my books, so take a look...
Also, I never have taken a Geotech class in college, so If I can do it, you can do it.
Good luck mate, go crush.