I have created thousands of thumbnails till now and the most important thing that I have learned is it's all about experimentation, there are no rules and guidelines all you have to do is learn, experiment, iterate and observe.

For me thumbnail designing is not just about the visuals, but also the storytelling and overall concept of the thumbnail. It's like trying to juggle creativity and logic, but hey, that's part of fun! Here are some thumb-tastic designs that i have created :)