This first Quick Auto-Masking tool is for mostly round large objects, such as faces, flowers and some other round-ish separate objects...

 

All what it takes is to draw a rectangle around the object while keeping the inner circle all inside the object.

 

For a face:

 

 

For a flower:

 

 

Cumulative Quick Auto-Mask.

You may not get the mask correctly on a first trial. The good thing is that Quick Auto-Mask is are cumulative - that means it will add to the existing mask, not replace it.

So all you need to do is to repeat over the parts that were left out.

 

 

Tip:

The blue circle has to be all inside the object, if the circle goes outside the object then also part of the background will be selected. Therefore this masking is not suitable for thinner and less round objects because the mask will "bleed" to the background.