how do actives decide

all of it.

Based on how much we liked you. So, conversation I suppose, though you won't always be able to tell how well it actually went. Just be yourself and let the conversation flow naturally. :)

To be completely honest, actives aren’t allowed to discuss their selection process.
The most we can say is to be yourself, don’t be shy, and make sure you’re meeting the requirements!
Don’t be dead set on one sorority because you never know what may happen. I know it’s stereotypical to say but trust the process because you’ll end up where you belong!

It’s a secret, and every sorority ranks those things differently. Prepare your best for each of those categories. Also, make sure you have a good rush resume

Be genuine. Answer their questions wholly. Ask them questions back. Ask open ended questions. Ask about their aspirations, their family, their experiences. “Tell me about a time when your sorority helped you through a tough time.” “Describe how this organization is shaping you into the leader you aspire to be.” You are becoming a part of a sisterhood for the rest of your life, it’s best to pick one that is helping their members become better women. Challenge them to translate that to you.

Now I’m a guy and have never been through recruitment but I bet if you do the above you will blow them away. Good luck!

Be yourself, trust the process.