So, you now know a lot of people, including girls in the chapter. That's great! Tell them - no pressure, just mention it - that you're interested in rushing again. See what their reaction is. If it's encouraging, sign up.
You'll need good grades, and a sterling rep.
Find recs...polish your wardrobe and conversational skills.
Go in without any expectations, just go have fun and enjoy the process. You've got nothing to lose, right? If you pledge, great, but if you don't pledge, you already have lots of friends and a life.
Don't think you'll only accept Alpha Alpha Alpha sorority or nothing. Be open to any of them.
Best of luck!