Keep it simple, no more then 2 pages max - ideally one...
Think from the reader's point of view - they have to trawl through 100's of resumes.... so it needs to be VERY punctual, to the point, clear and concise. It needs to convey the exact information they're looking for (think key words) in as little space as possible.
If the reader has to go through a load of waffle bullshit on the first page before they even get to a nugget of information - it'll be straight in the bin.
WORK EXERIENCE - Bullet points - dates, key repsonsibilities and skills learnt - BUT BULLET POINTS ALMOST... not waffle...
EXTRA CURRICULAR ACHIEVEMENTS - Simple, concise - not - i like to goez skiing in da mountains.... show leadership experience, team work and that you're goal driven.
Get a parent or teacher to proff read it and give you feedback - someone who can read it cold, as if they were the scholarship selection peeps....