Thanks for dropping in to our forum. Soooo let's get to business.
First things first... now although you do have some good UG numbers and fine work experience, my first impression from what you write is that things are very plain. Not to say that YOU are!!!!
But maybe you need to rethink your approach. Right now though I don't see anything jumping off your profile that says to me "Accept me!" and if you want to get into the likes of the schools you listed, you HAVE TO have that!!! So what is your unique selling point? What leadership do you have? That's something you need to think about as you will really need to present your unique case if you are to get accepted.
Now let's get into your questions:
1.Evaluate my chances of Admission in Harvard, Stanford, Columbia, Wharton & London Business School.
Depends on your GMAT and Leadership. But these schools will all be tough, no matter what GMAT you get.
2.I want to apply on 2nd Round? Will this affect my chance of admission as compared to apply n Round-1
1st and second round have comparable chances, so you don't need to worry about that.
3. Give some valuable advice to improve my profile further before applying to top business school.
Most important - come up with your unique selling points and passionate story. And secondly, beat a 720 on the GMAT
4.If I had a low GMAT score(below Average)in my 1st GMAT Attempt, will this affect my case?
If you have below a 690 your chances will be quite low at the above schools
5. My present Age is 28Yr, mean at the time of admission will be 29, Is Age factor also considered by the admission committee? and will this affect my chance of admission or do i need to put extra efforts to cater this factor?
28/29 is totally a normal age to go to B-school, so don't even think about it twice.
6. In 2007, after numerous tests and interviews,i was also selected as the "FLYING OFFICER" in Pakistan Air force, Al
Could be a nice story, but it depends on what else you have and what you might use instead,
Hope this helps you!
