A few thoughts in addition to the excellent advice above.
- Take our student membership of the Society of Flight Test Engineers and aim to attend any meetings available to you.
- As well as learning to fly, look to breadth of experience - different types, control systems, classes. Anything you can get, and learn from it.
- Your ability to observe, analyse, and write will be as important as your technical and flying ability. Develop those skills too.
G