Whenever you find yourself bored about anything, try making a color splash photo effect. I can bet that it will bring out the inner child in you. It's something that we did early in our childhood years. It's something that I find pleasing to do as an exercise during my early years of school ~ coloring!
The idea about this effect is very simple. The first step is to remove every bit of saturation on the image and then bring the color back onto the part of the image that you want to have its colors back. The subject of the images has to be the one in color while the rest are desaturated until it becomes black and white.
The best photo that will nicely in this effect is a photo where the subject has a strong hue on them. We need the main subject to have the most vibrant colors among the rest of the elements of the image.
For the first image, I have here a dashing set of red cherry tomatoes.
In this image, I chose the ones that are clearly in the focus while setting the rest into black and white.
While for the 2nd image, I have here a vibrant yellow flower.