SQUARE YOUR QUILT TOP !!!

I feel like this is a dumb question but here goes, How do you square up your quilt top? I've only been seriously quilting a short time, and so far I really havent had to do this. I really feel silly asking, but, everyone on this blog is so helpful and full of information. I'm making a quilt for the "Quilt For Kids". So I'm trying not to make any big mistakes.

Thank you all for making a great QWU blog!