Here is a tshirt I embellished and gave to my sis-in-law for Christmas. It is fairly easy and does not involve great sewing skills- just needle and thread. I cut three sizes of circles, stacked them, pinched the middle and sewed the middle to make the flower. I then sewed each one to the shirt with needle and thread.
These aren't the best photos, but the best I could do since this isn't my size. Thanks for looking. I'll be linking to some of the parties on the side.