Unlike psychometric test conducted by FPSC, it holds pivotal importance in MOD. Your selection for the interview will be decided solely by your performance in the psychometric test as it is a must step to clear for the interview process. Your marks in the objective and subjective portion will be considered zero if you fail the psychometric test, even if you are on the top of the merit list.
A careful approach is needed to clear the test. Important thing is to control your nerves so that you would handle the technical questions. Mathematical questions questions, Analogy, picture-story-writing, sentence-completion, situation handling questions ( For instance, you are a leader of an operation and one of your teammates is leaking information to enemies. what steps would you take? (a wrong answer to this question would be, "I will inform it to the head of the organisation or any other higher authorities..(which contradicts when you are already the leader)...
Or, you are in the middle of an operation when you realise that what you had done was against the interest of the institution, and you cannot undo it because of the limited time for the operation. What would you do? and similar types of questions can be asked.
In the whole process, time is key to success. Never stuck yourself at any question. If the statement of questions in the mathematical portion is lengthy, just skip it. Another important trick is that they can place easy and solvable questions either in the mid or at the end of the set. Your handling of the situation can either make or break the road for an interview.
Note: My comment is based on my observation which cannot be taken as guaranteed.