This challenge is about creating Bokeh and Starbursts in your images. Both phenomenon are dependent on lens (specifically aperture), points of light and placement of subject.

Tonight will be bokeh information and tomorrow I'll add starburst. There are volumes of internet information about each.

"Bokeh" refers to background or foreground blur in an image. "Beautiful" bokeh is created when the out of focus areas are smooth and stunning. Bad bokeh refers to too detailed (sic -who decides what's too detailed, I ask myself), jagged out of focus areas. It is complicated. Wide apertures (f4 and wider) and/or greater distance between the subject and the background, create better bokeh. Different lenses will produce different bokeh shapes (circles, hexagons and shapes between).The blades in the lens create the bokeh - the more blades in your lense the more circular the aperture and thus, the more circular bokeh. Choose a background with points of light and position yourself closer to the subject and the subject separated from the background." (from one photography article)

Another article concluded with "Good bokeh pleases our eyes and our perception of the image, therefore, the background blur should appear soft and 'creamy' with smooth round circles of light and no hard edges"

Holiday trees with their points of light can make for some beautiful bokeh. One thing not mention was - now, there are bokeh presets which can be added in post. I will NOT be rating anyone's bokeh.