I've just done my Graphics course at uni.
There has been lots of advice been given out, some of which I believe is the best.
Forget about the intricacies of typography, layout, websites... You are young, you have time, and THAT is your biggest advantage.
This is what advice I would give you, and what I would do if I had to do it all over again (Some of this has been said already):
1) Never take yourself too seriously, at any stage in your design 'career'!
2) A pen/pencil and a pad of paper are your BEST friends. Draw things which interest you, even if you don't know why now. WRITE things down that interest/anger/upset you. Then ponder why? Having a perspective of the world at 14 is only something you get once
3) Draw, draw, draw and draw. Anything. Then go to still life classes, sculpt/paint/build/take apart... Look for the unconventional, if someone says something isn't 'art', ask them why and challenge what you think. Find out, and research other Artists, a variety of artist from Tibor Kalman to Jackson Pollock.
4) Take an english course!!!! I can't stress that enough. Design, especially Graphics design, is all about
communication. Different ways in which you can express something through words, as well as visually.
5) Don't forget other subjects such as Maths, Design Technology,Art, Drama and Music! They will be vital sources of inspiration where original designs come from.
6) Enjoy being young, do lots of other things besides anything design related. See a film, date girls, play in a band... enjoy sleep (you'll find out why
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