I use a sticky washaway vilene in the hoop then I put a fusible cut-away on the back of the shirt and stick it to the hoop. I ALWAYS use a wash-away as a topper. I add extra tear-away and/or wash-away under the hoop for dense designs (like many that come from embroidery library). I also baste the it all together with a wash-away thread before I stitch the design. I really try to keep it stable to get a better stitchout.
I always use sticky tear away stabilizer,and just stick the shirt on the stabilizer; I never hope because it shows later on.
Iva, I see you have some great answers - I like to hoop my mesh cutaway stabilizer, then pin the shirt to that - with an added WSS topping - then I pin up the shirt around the outside of the hoop - to keep it out of the stitching area. *4U
I haven't done anything on a t-shirt yet, so I can't help. I know you'll do a great job. Reva
I don't like to hoop the t-shirt. This avoids the hoop burn. I use a basting spray.
a tutorial here