Being a huge MW3 player myself, I frequent the big commentators on YT. One thing I noticed is that even the big names have their best games against people who have yet to prestige while they are on a team of experienced players. It's nothing to be ashamed about. You'll never got 60-1 against a team of pros, and unless you're playing TDM, your last concern should be your k/d with professional gamers.
Anyway, on topic, your goal will be to get at least 10 people to subscribe before you put any video up. I guarantee nobody will want to be the first to the party in anything, and that includes subbing to your channel.
Then, you put up a video and you go the big names related to your channel. Subscribe to the recent commenters on their channel and add them as a friend. Leave a friendly channel comment, related to one of their videos. If you absolutely must throw in more incentive for the person to click on your name and go to your channel, say you are doing the same thing as they are. Do not ask for a sub, do not ask them to check you out. If you want, drop a comment every few days on a big channel telling people to check you out. Keep it from sounding like spam, and avoid burning bridges by spamming a wall that's not already full of spam.
Do not, ever, do "sub4sub." It skews perceptions of popularity, and while having 10,000 subscribers looks cool, getting <500 views per video does not.
A contest greatly speeds things up. One thing to keep in mind is the quality of your prizes is insignificant. My first two contests gave away store-bought decks, and my most recent and extremely unpopular (by relative terms) contest is giving away huge prizes, probably bigger than any other card channel on YT.
Lastly, don't get into it for a whole bunch of fans. You want to address people personally and be confident, both in your videos and in your comments. One thing that draws people to smaller channels is knowing that the creators are more likely to give someone attention. Give your subscribers and commenters attention and you will reap the benefits.
This all works great for the first 500 or so subscribers, and after that I found my channel growing on its own. On average, I get 5-20 subs per day on the slow days with no new videos.
Oh, and remember, new YouTube no longer emphasizes the importance of subscriptions. Now, you will want to have people pin you to their top 10 so your videos get views.
Whatever you do, keep all your videos high quality. Don't stoop to the level of 500 videos in a year that all have <200 views. I won't name names, but some of the bigger YouTube card "stars" simply upload 5+ videos per week along the lines of "I GOT A NEW DESK" and the result is purely short-term benefits.
I hope that helps!