Here is a flower shot. This was shot at f/11 to get most of the flower in focus but to get the angle that I thought worked the background separation isn't enough. Aka, when I got home and looked at it I was not impressed. There are ways to get the separation while taking the shot and ways to do it in software. Given I didn't find a way while taking the shot here are 3 ways I used in software:
- blurred background (looks like shallow depth of field or background farther away)
- darker background (looks like background in shadow or subject in brighter light)
- less saturated background
In Affinity Photo, a Photoshop alternative, I duplicate the image layer. Then I select the flower using the Selection Brush Tool. Then on the top (subject) layer I select Mask Layer. The top layer now will just show the flower.
Turn off the subject (top) layer and select the lower (background) layer. I use Affinity Photo's Inpainting Brush Tool to paint over the flower aka everything within the selection area. The app then uses area outside of where I painted to fill the flower area (see 3rd image). Now remove selection area (escape key in Affinity Photo).
The flower is removed from the background (lower) layer because if it isn't when the background layer is blurred in the next step the flower content of that layer would blur and show around the edges of the flower on the subject layer making the edges not look as sharp.
Turn back on the top layer to show the flower and apply a Gaussian Blur to the background (lower) layer. This gives the blur that looks like you shot with a shallower depth of field.
Next the background layer is darkened a little. This gives a little more separation.
Another change that can be made is to lower the saturation of the background layer. This helps the flower separate from the background a bit more.
These 3 adjustments to the background of blur, darken, and desaturate can be used together like done here or in any mixture. The key is not to do any of the changes to the extreme or it will be obvious and just look wrong.