The first thing I do is cut all of the T-shirts in half along the sides so I have a nice flat front and back. I usually cut around the sleeves to completely remove them from both halves. Unlike most, I interface after I cut out the T-shirt emblem instead of before. I lay the T right side up on my cutting board. I use my 12 /12" square up ruler to center the design as best I can, sometimes they can't be perfectly centered because then you are up into the ribbed neck hole of the T and you really want to cut below the neck line seam. I then cut out the imprint at 12 1/2 (or whatever size I need/want) then transfer to my ironing board and put on the interfacing which I have precut to size.