College

One thing I wish I did for myself - if I could go back in time and start over as a freshman in high-school - is look up essay prompts for college applications and begin thinking and writing about these prompts. Starting early will give you more time to think, reflect, and revise your essays. Of course, the prompts are different every year, but it's easy to accommodate college essays to many different prompts. Here is one of them from CommonApp this year:

Think about an incident or time when you experienced failure.  How did it affect you, and what lessons did you learn?

When you have a lot of time and no pressure to consider this prompt, you will be able to expand beyond what a normal college applicant would say. You may realize how bad you are at writing, but that's why you are doing this before it becomes a necessity - to be prepared.

UT Austin 4

For incoming Longhorn freshmen, here are some summer research opportunities and programs:
http://cns.utexas.edu/research-experience/undergraduate-research/summer-research-academy

Also, you should apply to the summer bridge program even if you aren't "invited". I wasn't invited, but I got waitlisted (and then denied). I am aware of one person who didn't get invited and got it, but I don't know a lot of people, so I am sure there are others. Here is the link to that for all of you rising seniors: http://www.utexas.edu/enrollment-management/programs/summer-bridge

UT Austin 3

The UT electrical engineering department has free seminars every two or three days over relevant, applicable topics.

Check it out: http://www.ece.utexas.edu/events