IAM,
Get hold of practice IQ questions. I used an old 1960's book called "know your own IQ" or something which had things like number sequences (ie. 2,4,6,..,10 etc)and cryptic symbols where you pick the odd one out. No idea if these are contained in the tests these days, but it came in very useful. There are also practice aircrew aptitude tests out there somewhere too.
Melch