Consistency

Remember:

No one's asking you to do all of this- pick a few things that interest you; but pursue these activities CONSISTENTLY. They want to see dedication- it is better to take part in a few extra-curriculars than do multiple things badly.

And of course- your main focus still need to be your grades. It's great if you can manage to do the things list above, but your first priority is academics.
There's no point spreading yourself thin leading several committees, and then not making your offer.

Most of all: have fun. Make sure you do things you ENJOY, not just activities that make your application look good.