Let's discuss your post in different components, sound good?
Academics: GMAT - a 720 is a great target. It's hard to say what you need at this point but for you let's go with "the higher the better". A 680 is a solid score but you need be in the 700+ club. Your GPA(s) are average and within the range. They won't hold you back, but they won't help you stand out either. Effectively, they're a non-issue. So you need a great GMAT to stand out.
You say you have a Masters - in what exactly? Some programs don't like masters degrees, some are ok with them. Also, your story for "why an MBA" will need to be crystal clear. This is important for everyone but when you have an engineering background and (I assume?) a related masters, that makes it critical for you.
Work experience: ok, so here you're a little light. If you can't easily demonstrate leadership (people, thought, etc. - there are many types of leadership) then that's probably a sign that needs to be heeded. Your small business experience, however, DEFINITELY should be highlighted. That's good stuff man! And chances are you learned more doing that than most other activities so yes, include it. As for your professional experience, what did you actually do? That's important and I can't get that from what you've shared.
Origin: Australia isn't hard, it isn't easy. Yes, India and China is a hurdle for those applicants but for you, you're merely vying for the international spots without much bias for or against you. You're going toe to toe with Brazil, Denmark, Russia, etc. However, what's your ethnicity? That factors in.
Extracurriculars: you haven't mentioned this at all?
Overall, I could use a little more information so share on! I'm happy to help but want to make sure I give you the best possible advice.
Managing Partner, Founder
Critical Square | MBA Admissions Services
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