Learn much math as you can. It's the language of the way the uiniverse works. Read it and speak it well. Technical skills are important when you work with fancy equipment. It sure helps to know how to fix machinery and electronics.
Astronomy is really a people game.
I used to think that science was not a field where people interaction was important, but I was wrong. Astronomy and science are VERY people-intensive professions. Speaking in front of people is also crucial skill no matter what field you are in. Learn to do it, and do it well, even if it terrifies you. Practice writing every day.