So I have a Cool master 212+ http://www.newegg.com/Product/Product.aspx?Item=N82E168... but I'm not sure I have the fan mounted in the right direction. I have a rear, top and front fan in my case. I assume the front fan is an intake and the other two expel hot air. I have the fan mounted on the heatsink so that it is parallel to the rear fan and mounted to the right of the heatsink just like in the diagram for the heatsink on the box. However I can't tell if it is pushing air to the rear fan or not.
My fan is mounted in a similar way to how it is mounted in this guide at step 10 when he shows the entire system, however again mine is parallel to the rear fan and mounted on the right of the heatsink.
somewhere on the side of your fan are two arrows pointing 90 degrees apart - one shows the direction the blades spin, the other shows the direction the air travels. You want your fan blowing towards the back of your case