Best way to texture large terrains?

How can I get rid of that repeating "checker" type pattern from showing up when texturing larger terrains?

For example, if you have a large mountain range and use the Cliff (Layered Rock) texture for a good sized area and get back in a distance you can see the repeating textures. I will be working with someone who will be doing all the texturing and modeling soon but right now it's just me and I am poor at this part. Not sure how to make it look seamless

(Copied from: http://forum.unity3d.com/viewtopic.php?p=330175)

What you are seeing is low frequency detail in the textures repeating over a large scale.

When creating textures, in addition to make sure they tile nicely at the edges, you'll also have to make sure there are few low frequency details that show up as patterns when zooming out.

Gamasutra had a nice article on how to use the high pass filter in photoshop to do this