Light Bokeh Portrait
1) Choose background which contains lights or select night lights.
2) for foreground i already cutout the image.
3) Duplicate background layer and convert to smart object.
4) goto filter and select tilt -shift from blur gallery.
5) Now adjust blur amount depand on size of your background.
6) Similarly adjust light bokeh and light range.
7) Once you are happy with lights click OK.
8) Now drag foreground image onto background layer.
9) Light bokeh layer is smart object so we can change adjustments any time.
10) Here is final before and after results.