Their are many books in the market which will help you in the aptitude and the reasoning part.Since i dont know your educational aualifications i cant guide you in reference to name of books but you can you to a good book shop and ask him for a book that contains multiple choice questions of your level.
same applys for maths and science of your level.
If you are planning to solve previous year question paper then its goo because it will give you a fairly good idea of how exam is going to be about and what will be the level of exams.
Try some online aptitude tests to check your speed and focuss more on the areas where you are strong.
You might be having the syallabus of the exam ... among those priortise the the topics fo your intrest and work accordingly.
try solving a previous year paper and see how much time you are taking...
be focussed on accuracy in comaprision to tyring maximum no of attemps bcz the exam may have a negative marking.
Good luck for your exam