if you want to get good at aptitude tests all you need to do is practice! honestly i practiced and went from below average to genius level iq in about a month!
the best
aptitude tests practice that i have used is at aptitudehack.com, the free stuff isn't that great (not many questions) but when you signup there is loads of questions and you can't fail to improve!
it also has an
aptitude tests forum where you can post questions about your aptitude test problems