saygan - Welcome to GMAT Club!
As far as the GMAT is concerned, I would highly recommend that you take the test early so that you have one less thing to worry about. Some times, people take more than anticipated time to prepare for the test.
1. No, there is no general trend that you must abide by in order to make your profile appear more attractive. Ultimately, it's the story you tell that matters.
2. Start-up work experience is always attractive because it shows a plethora of talent and skill-set.
3. Absolutely yes, your experience in running a small-scale business will definitely count and will provide you will better brownie points.
That said, I would advise you to post your complete profile, including undergrad score, target GMAT score, target schools, extra curriculum, among others, in the
profile review section.