I also ended up using Heat n' Bond to adhere my fabric cutout to the onesie, but you could also use fabric glue.
Then, all you need to do is follow the directions on the package.
Once the Heat n' Bond was on my fabric I traced my dinosaur and footprints onto it and cut them out.
Then, I placed them where I wanted them to be and ironed them on. So quick and easy.
Because I know how often little onesies get washed I wanted to secure everything down. So, I did a quick little zig-zag stitch around the dinosaur. (The footprints were a bit too intricate to stitch around)
And, that's it. Such a fun way to cuten up a plain little onesie. And such a fun thing for a group of gals to do at any baby shower!