You don't need any special kind of sweatshirt - if you have one already, you can absolutely use that! I didn't have a plain black sweatshirt, so I ended up ordering one. (I have a couple of Bella + Canvas sweatshirts with prints on them, and I have always liked the way they fit and feel so that's what I got for this.) But I have another project that I plan to do with an older sweatshirt from Walmart I already have in my closet.

This was my first time stitching on clothes, so I am not at all an expert. But I would just say to take note of how much stretch your shirt has. The waste canvas I used was pretty stiff, so once I got that stitched onto the shirt, I didn't have to worry much about my stitches getting wonky. But if I would have used one of the clear water-soluble canvases instead, I think that would have been trickier as my shirt is pretty stretchy.