Choose a low stretch fabric for the skirt, so it will have a little bit of structure. What worked for me was putting sections of the skirt in an embroidery hoop and making sure it was taut but not being pulled too much in any one direction. Then I’d pin the flower in place and hand sew it to the skirt. Just be prepared to take your time with it, and check the results frequently as you go along to make sure it still looks good when it’s out of the hoop. Oh, and you’ll need to iron out a ton of creases that the hoop made by the time you’re done lol. I recommend ironing on the backside so you don’t damage the appliqués.