I must admit, for my photoshopping endeavors, I have tried to make repeating patterns and failed miserably. (Like the plaid shirt fiasco for "Chosen" Xander, BTVS). Apparently I have been doing it the hard way!
Julia Rothman, one of my favorite illustrators, uploaded the "headsmack cause it's so easy!" post on Design*Sponge. She shows the old fashioned way of making a tile-able design! Brilliant!
And check out some other patterns she does. Genius!