As a Local Guide living in Austin, Texas I can honestly say I have yet to live in a better city (within the US)... and trust me when I say I have lived many, many, many places. So what's the secret? Well, I wont go into detail here and leave some room for you to explore and to establish your own opinion.
One TIP to keep in mind when in Austin:
Blend in! become a local, assimilate, get weird, be authentic, find a true local and have him show you around. This tip should hold true for all your travels. not just this one.
If you truly do not have a clue where to start and you are tired of reading random tips and guides then give my custom picked & local itinerary a try. Don't forget to leave feedback if you do!