Branding and marketing are two separate things and both incorporate a lot of elements.
Branding includes the name of your channel and all visual aspects such as your logo, banner, thumbnails, endcards, etc. It also includes the core values and slogan that your brand is to represent.
Marketing includes the promotion of your channel and its message. It means figuring out who your target audience is, where they are and how you can reach them. It means figuring out which social media platforms would complement and help your marketing strategies. It includes your upload schedule, your interaction with your audience and much more.
So after establishing the terms, what is your actual question? Which marketing strategy we use? That won't help you. As a travel channel, I have both a completely different branding and marketing than a gaming channel. So first establish for yourself what kind of videos you make, what niche your in and who your target audience you have.