Well, this is a pretty vague question because it will all depend on which personality Trey has, what are his possibilities, etc. But I can help you try to make some kind of list that would help everyone if having the chance to follow it.
The first thing Trey has to do is to be sure what he likes doing, see what he enjoys in order to realize what he wants to do in his future.
After making this big decision, he has to study to be good at what he wants to do. If we are doing something, we better do it right. It is important to do it seriously to succeed. If we don't love or feel passionate about what we decided to do, we won't succeed at it.
And the last thing he should do is be patient and work hard to achieve the future he imagined. All good results are consequence of hard work, responsibility and good intentions.