I recently passed FEAST I exams to become an air traffic controller. Next round of tests is a FEAST II radar test. What general rules used for air traffic guidance should I learn in order to be prepared and easily understand the test instructions?
You should not learn any ATC rules in preparation for the test.
Prior preparation is normally not required for FEAST. Abilities like spatial orientation cannot be learnt. It is true that there are books on test preparation on the market. However, we do not recommend relying on these books as they can give incorrect information about tests or promote inappropriate strategies which may result in negative results in FEAST.
As with FEAST I, FEAST II does not require any previous knowledge. Each test segment is thoroughly explained in advance. Part of what they're testing is your ability to understand and put to use these instructions.
While parts of the test do resemble certain aspects of the job of an air traffic controller, the testing environment is simplified and adjusted to fit the testing needs.
I took the FEAST tests some years ago, and did have a fairly extensive knowledge of ATC in advance. While it probably did help me in some ways, I think it was also a disadvantage in other ways since the test both simplifies and changes some of the ATC rules and regulations.
As I'm sure you're tired of being told again and again, the best way to improve your chances is to show up well rested, well fed and be sure to read the test instructions very thoroughly (and be sure to ask if you are in doubt about anything).