I purchased a fat quarter from a LQS that was folded the neatest way. I hope I can explain it to you with these pictures. When fat quarters are folded like this, it makes them organized and easy to look at when choosing colors for a quilt.

fold the fat quarter twice, lenghtwise
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then fold in half again
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bring end with selveged edge up
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tuck the folded edge into the selveged edge
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this is what the finished fat quarter should look like
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