Checked out your channel, and I have a few suggestions:
1. Maximize your tags. You only have a few, but you can have up to 500 characters. Make sure you have the game, popular terms in the game, platforms the game is on, and anything else relevant.
2. Include popular channels in your tags. For the video you're doing, do a YouTube search. Include the names of the top 3 or 4 channels in your video tag. This helps your video show up as a suggested video when people watch those other videos.
3. Your title and description need to have what people are searching for. For your KDR videos, I'd have something like "How to improve KDR" included in both the title and description as well as the game and a question that would interest people. "Want to get better? How to increase your KDR in Black Ops 4!" or something like this would work.
4. Be active in social media. Saw your Twitter, and it looks like you're not really active there. There is a HUGE presence for BO4 and Fortnite there. I'm sure there are plenty of forums and FB groups dedicated to these games. Contribute to their discussions and don't spam your videos. After a while, you can make replies that you covered that topic in a video. Get them to know you first as someone knowledgable and worth checking out.
5. Be active in social media. Yes, I said it again because it's that important. How is this relevant to SEO? The more views you have the higher you start getting placed in search results. Search "geforce giveaway" on YouTube. My video shows up as #2, only behind a video from Nvidia themselves, and beating out even all their other past videos. It doesn't have nearly the views as their videos, but places very high because I promoted the crap out of it on FB and Twitter.
Hope this helps.
