Don't know if you are still taking advice but I have watched this one guy's video on advice for doing Gaming videos on YouTube so I figured I would shorten that and explain it to you here.
First of all, when going into any sort of YouTube, do it only and ONLY if you actually enjoy doing it and it is fun for you to put videos out on YouTube and to make commentaries such as this. Don't go into this side of stuff and say, "Oh, I wanna become famous like Pewdiepie or some other guy!". Many YouTubers can agree with me in saying that shouldn't be your goal.
Secondly, Play games that you enjoy and think that you enjoy making commentaries over. Don't play games that you hate or hate trying to explain or talk about. If you hate FPS games like CoD and or hate doing commentaries over it, then find new games. For example, I love MOBA games, RPG games, and a few other types of games that don't involve FPS games.
Lastly, when going into doing these videos, have your mind set to have NO and I mean NO EXPECTATIONS or standards on a video. Do not think that your video will get even 1 VIEW. Say to yourself that it may get no views and you need to be fine with that because it may or will happen. I set a high standard for one of my videos and let me tell you that I was majorly disappointed, so go into this knowing that you may get 10 views, 0 subs, 10 subs, maybe even 100 subs, but do not think you will become big or even get 10 subs in a week/month.
There ya go. If you want to watch the video of the person that gave me this advice, look up on YouTube: SuperMCGamer How to YouTube