I agree with AlaskaBound's advice on the cog test. The best thing you can do to prepare is to rest and (try) to be relaxed and mentally clear when you sit down at the computer. Don't anticipate anything, just do what it tells you on the screen.

For the job knowledge, I approached some of the systems and aerodynamics questions more as a SAT question and less as an ATP written. Instead of 'which one of these answers is correct', I deduced a few answers by revising that process to, 'which one of these answers is not like the other ones'. Don't get too hung up on the math on some of them. Estimate in the ballpark and one of the choices will be close.