I understand is that you need to change 2 things and keep it regular and also change the videos you have already uploaded. 1. Your thumbnail should be attractive 2. Title and description should be optimized Eg: A person first looks at the thumbnail before watching a video and after looking at the thumbnail, if he likes it, then he watches the video. 2. You need to optimize the title and description to stay on top of the search results. You need to optimize in such a way that your video is found first when searched by a short keyword. If you work like this, you can expect your channel to grow very quickly.
I understand is that you need to change 2 things and keep it regular and also change the videos you have already uploaded.
1. Your thumbnail should be attractive
2. Title and description should be optimized
Eg: A person first looks at the thumbnail before watching a video and after looking at the thumbnail, if he likes it, then he watches the video. 2. You need to optimize the title and description to stay on top of the search results. You need to optimize in such a way that your video is found first when searched by a short keyword.
If you work like this, you can expect your channel to grow very quickly.
As a professional SEO expert and thumbnail designer, I can do these tasks for you professionally.