Spatial is all about getting the questions fast. You should be able to do them in 30-40 seconds, since you have 15 minutes for 30 of them. It sucks that you can't write on the exam; it'd make eliminating choices much easier. There are four things to look for:
1. direction of bank - to right or left? The side where the horizon is higher is the side it's banked towards.
2. Degree of bank. I believe on the test you have to distinguish between 30 and degrees. This is not as simple and I would leave this off unless the other three aren't good enough
3. Pitch. Up or down? Should be fairly obvious. For a banked plane, the foolproof method is to compare the amount of sky on one edge of the picture with the amount of ground on the other. More sky = climbing, more ground = diving.
4. Direction relative to shore.
You should be checking these in a rote manner. Practice until it's automatic. Use a hand as a model airplane if it helps you visualize. (I did). Position your hand as you go through each of the checks, using the edge of the paper or the desk as the coastline. Also, an easy check you can do sometimes, is to ask if the low wing is pointing to land or water.
The gouge from here is good for 70-80% of the stuff on the aviation/nautical part. If you get a ~70% I think it's passing. That section can be tough if you've never learned this stuff before; I haven't found a good central source for all the info. Know the dates of founding of the Navy and the Marine Corps, what Tun Tavern is, who John Paul Jones is and why he's important. Look up the Marine Corps and Navy in an encyclopedia (wikipedia.org is a great online one) and know the early history.
Nautical: take the test here. You can ignore the safety stuff. The important things are nautical terminology, and markings for sea lanes.
http://boatingbasicsonline.com/
I studied from the FAA's Pilot's Handbook of Aeronautical Knowledge. It's a bit overkill but it does have everything the Aviation part covers (minus some military things). Things you will want to know: how runways are marked. terminology for various cloud types, and basic meterology.
Of course, know the parts of an airplane (you do want to be a pilot, right? :-D ), various propulsion systems, and the typical instrumentation. The handbook is a good source for all of that. Try to find it in a local library or perhaps from pilot friends. I ended up buying it.
Good luck!
