There'll be plenty of books out there on how to ace aptitude tests etc. but they'll mostly cover numeracy, verbal reasoning, logic etc...the kind of skills broadly looked for in many careers. Run a search for "aptitude" at Amazon. Also see:
http://www.morrisby.com/#http://www.....morrisby.com/
Specific piloting skills such as a measure of hand-eye coordination, multitasking ability, etc. tend to be more inate though if you've ever been an avid computer gamer you might have a slight advantage...!
I don't know of any FREE tests/exercises similar to the one I posted earlier. Where there's a market, there's a price
Good luck,
V1R