First I designed the shirts using the Silhouette program. However my printer decided to go berserk and have an imaginary paper jam that Beau couldn't fix so thankfully Grandma helped us out and I printed out the design on the iron on transfer paper on the printer at her house. Then after the kids went to bed I took the printed design and used the Silhouette cutter to cut around the designs to remove all the excess iron on transfer paper.
Then I removed the excess iron-on that wasn't part of the design. It removes easily and perfectly from around the printed design because of how wonderfully the Silhouette cuts - it can read the registration marks printed on the paper so it knows exactly where to cut after you've printed out the design on to the paper. I placed the design on the shirt, covered with a kitchen towel and ironed it on to the shirt.
Once the iron-ons had cooled off I peeled off the paper backing and voila. I had a little issue with the edges not coming up cleanly in some areas. On Abby's it's less visible and just little parts around the edge. Micah's had a little bigger issue in one corner but just in that one corner.
I hope these will hold up a little better than the pumpkin shirts did.