Once you get the smooth areas done, you can tackle the areas where you’ll need to invent new detail. Here, the Clone Stamp (and all of its options) is your best friend. Type S to get the tool, then go to Window > Clone Source to see all of its awesome controls (note: you can access these for the Healing Brush, too). Click the Flip Horizontal or Flip Vertical icons to grab flowers from the left side of the image and clone them in reverse on the right. You can also rotate the clone source as much as you like. Since pattern repetition is a clue that the image is retouched, do your best to transform the data you grab from other areas in the picture.