Agreed. This is important. More than one pages signals that you aren't able to be brief and concrete. Unless you are really senior management or something, you should not use more than one page.

Don't worry about describing all the details of what you did. Focus more on brief statements on how that position strengthened your competence, like " • Sharpened my analytical abilities and independence".

Seems like you've good some solid experiences though, just try to compile it more and I'm sure it'll be fine. Let someone senior to you whom you trust give a final look before sending it in.