Create a schedule for yourself that gives lots of time for study/homework with still a lot of time for relaxing and STICK TO IT. Planners become your best friend.
Don’t be afraid to mingle and make some friends! Join a club or two. Hell, you can make a friend right now if you divulge who you are.
Lastly, try to use what Texas State pays for! Trams, recreation center, tutoring at the Slac Lab, free computer labs, etc.
Hope you enjoy the university!