It always seems impossible until it's done.
Well I have cleared it twice, so you too can do it with ease.
1.Read newspaper, preferably The Hindu.
2.Solve RS Aggarwal Aptitude questions.
3.Practice non- verbal and verbal questions so well that you end up getting all answer right in AFCAT.
4. For English section in AFCAT, learn commonly used idioms, solve a few questions everyday.