Are you monetized? If so, then I really don't recommend posting the Link to the Past videos. Nintendo recently went on an idiot spree and started claiming all videos containing games they've copyrighted as their own, monetizing it if it's not already monetized and taking away advertising income if you did monetize it.
There's also the risk of a company claiming copyright to your material, so do some research behind each game you do to make sure you don't get any strikes against your account. Sometimes you'll find stuff like
this, which basically shows that a company is awesome. Be careful with sounds and music in most games, since sometimes those are actually owned by someone and looked for under Google's Content Protection Software. I've heard of problems over trap door sounds, of all things.
With that out of the way, the best way you can promote your videos is just being consistent. Make a schedule and post the videos. Honestly, I don't think folks would care if you made a thread over in Creative Projects about your channel in order to get feedback and get it started. I did that a while ago with my own channel, but I didn't follow up on making more videos. If you're curious, I've got a link in my signature, but I haven't done any videos for a few months and they were mostly things I did to test the waters. Once you're more established you can do what Max White suggests and post in the Play with Your Buddies section.
Once you've got a fair following behind you, you'll want to think about joining a partnership. I don't recommend Machinima, since they've kind of turned into Satan since they became popular, but there's a few other choices. Don't bother until you have about 10k+ subscribers and have a fair bit of consistency on your video schedule, though. No one will be interested until then. If partners are malls, the channels they host are stores. Stores that probably won't pull a profit or stick around for long won't get into the mall, even if that mall has no real size limit.
The big thing about being in a partnership is that it pretends to help protect you from copyright trolls and promotes your use of gaming video as Fair Use as you go on to more prominent games. None of them do a very good job of it unless you end up on the level of Total Biscuit or some such (And even then folks like Total Biscuit, commentator on one of the most popular gaming channels on YouTube,
can have a problem with it), but it's better than nothing. Most importantly being a partner helps your videos get promoted by other creators within the same partnership.
So just keep trucking. From what I've seen your videos are pretty good. You've got a non-American accent, which is one of the more consistent signs of success in the YouTube market, so you've already got more going for you than I do. You may consider editing the videos down to only the interesting bits, but it's totally up to you. Generally when I do videos every hour of game play gives me about ten minutes of usable video, but there's so many ways to do it it doesn't really matter. Just do what you love you'll be successful. Unless what you love isn't loved by everyone else, but you know.
As for the friend who already has a channel, take advantage of that in the cleverest way possible: Do videos together. For example, play a game where part of the video is on his channel, and the other part is on yours. Like, play a multiplayer game of Tomb Raider with two matches, with one match on each channel. YouTubers working together is probably one of the best ways to increase viewership for both of them, because it means that if someone watching his channel likes you, or someone watching your channel likes him, you'll both win out. Just don't do the "yeah, check out my friends' channel for no reason other than I say so". Just, "This is my friend, here we are playing a game together, link to his own channel in the description in case you cared".