You gotta use pins! It's a must. There are very few garments that I monogram that have zero pins somewhere in them while the machine is going.
I hoop almost everything I do, and the smaller the garment, the harder it tends to be to keep the fabric out of the way of your stitching area. Pins make all the difference. Pin the sleeves back, pin the neckline back, pin the body of the shirt to one side or the other....get the picture? Trust me. After numerous failed attempts....pinning makes all the difference. Happy Pinning!