1. Content- Make sure you have good content, what I mean by this is essentially do not be boring when commentating or presenting a non commentated video in a boring fashion. People do not like boring videos, basically your audience retention rate will suffer and that is something you do not want at all. It also may cause people to dislike your video and that will definitely not help your cause either.
So how to improve on this you might ask?
when commentating be lively, crack jokes, and be relaxed. Make sure not you do not copy any big time commentators out there, for example do not specifically try to commentate like WhiteBoy7thst, Tmartn, or Syndicate. People will spot this very easily, dislike your video and probably write a hate comment. To avoid this, say you like how the three of them commentate. Well then, take aspects that you like about each of their commentations, combine them together and put your own personal spin on it. This is called drawing in inspiration, your just adopting ideas, remaking the ideas, and creating your very own commentation style. Picoso did with his paintings, he drew in inspiration from his surroundings, created an idea in his head, put his own spin on it and made it into a masterpiece. My philosophy is why can't you do this with your commentation style?
For those who make non commentated videos how would you improve on you content?
In your case it's all about making your video visually pleasing and maybe adding an awesome non copyrighted sound track. What I mean by visually pleasing is edit your video so you have cool transitions and also shoot your video with interesting angles if possible. Depending on the type of video your making you might want to add a non copyrighted sound track. Sound tracks can add emotional feeling to your video, say your making a Call Of Duty sniper montage you might want to use some kind of hard rock or heavy metal type of soundtrack because it adds a feeling of epicness to the video. You also again want to edit the video so key transitions in the music translates to what happens in the video. In this case a sniper shot across map connecting to a target for a headshot with a shaky effect at the same time a guitar bends in the soundtrack, then your viewers be like hellz ya bro!
2. Respond to your subscribers!!! people like to have interaction with the commentators they are subscribed to. It makes them feel as if they are apart of the channel, they feel as if they have a connection with you and that is excellent. This will produce active subscribers, the people who come back to watch your videos and give you some interaction.
3. Do not sub for sub!!!!! sub for subbing is in most cases pointless because chances are that you will only check out that person's channel once maybe twice. He or she will probably do the same, in essence all this does is create inactive subscribers and that does not help your cause. They are just a number and that is all, sub for subbing is not an effective way to build a successful YouTube channel in my opinion.
4. Create video responses to your own videos. What I mean by this is say you start a Minecraft let's play series on your channel and you upload your first episode. When you release the second edition to your Minecraft let's play make a video response of your second video to your first video. This puts it in the comments area enticing viewers who are leaving comments to maybe click on the video response. This is a very tedious task that I absolutely hate doing but I have seen the results in the analytics of my videos that it works for the most part and is definitely worth doing.
5. Make playlist of your videos in a series and put them on your channel's playlist side bar. Again this makes it easier for viewers to watch specific series created by you.
6. Link your videos that are in a series with annotations!! After uploading a video add some annotations and link them to your previous as well as your next video. This makes it super easy for viewers to get to the other videos in the series. You can also get fancy and on your next annotation you put a link to your next video in your playlist. What this does is when a viewer clicks the next annotation on your video it takes them to your proceeding video in your series playlist. This gains you more views because now the viewer does not have to do anything at all to watch as many videos as they please in your series because the videos auto play through.
7. Use Google AdWords to help you tag your videos. Basically this allows your videos to be found much easier on Google search engines. How I do not know but it's a tactic I have been using for quite sometime now and it has been working beautifully. Plus using Google AdWords shows you the competition you will having using each tag, if it will be low, medium, or high competition. You want to aim for the low competition tags, they bring the best results. If you need a guide on how to use Google Adwords for YouTube go to YouTube and search it you will find plenty of guides out there to assist you.
8. Market your channel and your videos!!! For instance create a twitter account for your channel, put in your bio that you are a video game commentator and put a link to your channel. Start reaching out to fellow gamers by following them and they will most likely follow back. Also join forums and become active members, this is a slower process but is definitely worth it because you establish great relationships with people, gaining their backing and support. Do not video spam, it will just get you banned as well as a bad name, there is no point and is not worth it.
Hopefully this guide has taught you some tactics that you can implement on your own channel. If you have any questions please let me know and I will do my best to answer them.