Hey man, just checked out your channel. I'm going to give you my opinion, and maybe give some tips on how you can improve.
I'm not going to talk about getting a capture card, because I'm SURE you've heard this already xD
Since you're using a camera, I suggest find the perfect position to place the camera to capture the entire screen, and only the screen. Preferably on a flat and sturdy surface to avoid shaking.
With your call of duty videos, I can't stress how important it is to have commentary on CoD videos. Back in the day, when the Call of Duty gaming scene on youtube wasn't so large, videos without commentaries were fine. But in today's youtube, videos with commentary seem to be more entertaining. MOST people will actually come for the commentary, not the gameplay, at least IMO.
Now, I'll be honest, I get lazy and sometimes I don't add thumbnails to my videos. But please, do not be lazy. Add thumbnails to ALL your videos.
With this advice, I think you can grow you channel into something larger
Cheers!