Make a Perfect Square

 

Take a rectangular piece of paper, and fold it bringing edge A over to meet edge B

The blue line shows where the crease will be.

Start the fold from the lower left corner.

Leave it folded and go on to the next step.

   
It should now look like this.

Go on to the next step.

   
Cut (or carefully tear) the top section off.

Go on to the next step.

   
It should now look like this.

Unfold it, then go on to the next step.

   
You now have a perfect square to use for origami.