They say the first impression is the last, indeed a true fact in terms of every social media content. Creating super content is not the only part of what makes your channel successful. But your video's thumbnail will help them decide whether to trust your content or not.
It isn't about planning out the face of your video but to have a polished look that makes your video look more presentable. Set yourself apart from others, mainly those who fall under a similar content list. It also helps in establishing trust and believe that you produce original content.
Before you lookout for a professional graphics designer, learn that thumbnail creator equates the same. It helps you cut down on time, money and effort. Select a template from the gallery that sits right to your need. Customize the design elements - alter the font style, add stickers, graphics, and icons, etc. Save the design once done and share it with your friends.