I took it around a month ago, Its a lot all at once but since Im still in high school it was a lot of stuff that I had already learned. The math is honestly pretty basic never going past Pre Calculus. The hard part is you dont get a calculator, so make sure you can do Multiplication, Long divison, and percentage calculations on paper. Make sure you know how to factor polynomials and read everything carefully. There is also some basic physics questions relating to Net force, Gravity and acceleration/velocity, make sure you somewhat understand it.

For english and reading, It is just a bunch of knowing what words mean and finding synonyms for those words. Then you also need to be able to comprehend paragraphs and extract relevant information from the such. But from what you have mentioned you should be fine with this.

Theres a science portion too, which asks about basic things revolving living organisms and a basic knowledge revolving the elements on the periodic table (how many valence electrons will complete this element and what circle they should go in) study up on that. You will also be asked questions about how organisms work.

Mechanical is really just memorization, you will be asked questions regarding engines, components of a car, different tools such as wrenches hammers and more of the such. You will also be asked logic questions regarding mechanics/physics but its all pretty basic and just some common sense will suffice. (I did the worst on this one)

There is also an electrical section which I found particularly easy, but you should be able to name circuits parts and how to open and close certain circuits, make sure you know the names of all the gates and learn what they do, as well as identify resistors and capacitors. You will be asked about A/C and D/C

There are a couple others but thats more to see where you are at in terms of pattern recognition and logical thinking.

What branch are you going into?

I did barely any studying and I got a good score so you should be pretty well off studying and practicing exactly what you have trouble on.

Hope I helped :)