You've probably seen pictures more than once in which the main object is in focus, and beautiful circles of different colors are visible on a fuzzy background. This effect is called bokeh, and you can easily achieve it without post-processing.
You can't do without light to create a beautiful bokeh. One of the easiest ways is to use the Christmas lights. The lights of the night city or the evening sun breaking through the branches of trees will also work great. You can even use crumpled foil illuminated by a lamp or flash.
It is good if the light source is small. It is even better if there are several of them. By itself, the sun will not help to achieve the desired effect, but the light passing through the leaves is quite enough. Remember that the color of the sources will also be noticeable in the photo. Use it.
Beginners often place the object they plan to focus on close to the background. In this case, this is a gross mistake: the further the object is from the background, the more the latter will be blurred.
The distance also affects the size of the circles of light: they decrease as the main object moves away from the background.
If you see that the subject is too dark, try to highlight it, for example, by reflecting the light with a piece of paper. As a last resort, you can use a flash or a flashlight.
The background blur is also affected by the aperture, that is, the hole in the lens. The wider you open it, the more pronounced the bokeh effect will be.
Set the camera to aperture priority mode. For example, on Nikon cameras it is marked with the letter A, on Canon — Av.
Then select a low number, such as f/1.8. Remember that the higher it is, the more the hole is closed. You definitely don't need the f/16 aperture, otherwise not only the subject will be sharp, but also the background.
If you have a regular soap dish or smartphone, try turning on portrait mode. However, in this case, you should not count on spectacular bokeh: the lenses of cheap cameras often do not allow you to achieve it.
When everything is set up, focus on the main subject and take a picture. Congratulations! Now there is one more cool photo in your collection.