Register for the summer orientation when it opens in March (I did the 1st session and it was packed but fun and registering for classes was easier, the later sessions are a bit less packed )

A few days before your first day of orientation (2-3), try to plan out your schedules  (do not try to get too ahead, I planned courses a month ahead and ended up getting a completely different schedule because classes got filled up), 

When the course schedule comes out, download "UT Registration Plus" to your Google Extensions, search up "UT Austin Course Schedule Fall 2024", and build multiple schedules just in case (also use Rate My Professor), some of you may be in honors, TIPS, or will have FIG's (first year interest groups (they'll explain it more during orientation)) which will reserve classes for you so you'll have a fairly easy time with registration

If you have taken and did fine in AP Biology, AP Chemistry, and AP Calculus AB/BC, you will have a breeze your first semester of college (I didn't take any of these any did not do as well as those who did, however, if you didn't take them, do not stress it)

Submit all of your AP scores and claim as many credits as you can (do not claim credits for Biology, Chemistry, or Physics (these will be required by medical/dental schools to be taken in residence at UT Austin))

Join organizations (search here Hornslink)  or rush Fraternities/Sororities (if interested), get ready to go to your Professor's/TA's Office Hours (Networking will go very far), refer to your Professors as Dr. X or Professor X

I personally sit at the front of my science classes so I am not distracted by others or my phone (it will range from 150-400 people in your general science lectures)

Here's a list of what I bought/have for my dorm and overall college convenience so far Dorm List 

Come in believing that you are still at the top of your class, you will meet a ton of impressive people but you can compete with them too (there are hundreds of Val's and Sal's, those with EMT jobs, and those who have worked in hospitals before but you can do even better when you overcome the inevitable "Imposter Syndrome")