First, forget about making money with youtube. I'm not saying don't monetize your channel, do that but never rely on that alone you need to diversify because they pay pennies. It's not a reliable income source even for popular channels.
To grow your youtube channel, you'll need to do some proper keyword research. Once you have all the keywords you want to rank for then you can create videos for those keywords. But always do some proper research before creating videos.
Metadata Tips:
Title: Don't rely on your main keyword only for the title, include related keywords as well. But make sure it makes sense and reads naturally without spamming. It should also be something that is in the video don't mislead people.
Description: I've tested this and it doesn't matter how long your description is, if you want to have a 500 words article then go ahead and do it. But even the video that only have 50 words will rank high, just make sure you can fit your main keyword and related keywords withing the first paragraph, again don't spam make everything read naturally. You can also link to some of your videos within the description, but I use the description to link back to my channel.
Tags: Do a search on youtube for your main keyword (you're going to do this for each video you upload) then click on the first 5 videos to check what tags their using. Simply right click then select "view page source" on each video to get the meta keywords. Choose the ones that are related to your video and include related keywords that you can think of.
That's what I do for metadata. Also use annotations and youtube has just added a new feature called cards you can use those for your call to action.
Make sure you're videos offer valuable content which will keep people watching till the end. Nothing beats high quality content that is worth sharing, if people share and embed your video online then you'll get good organic backlinks which will help your video rank high on search. Also create your own backlinks as well to improve rankings.
Use custom thumbnails to grab more attention and increase click through rate. Encourage people to like, comment, share and subscribe at the end of each video. Share your video on your social accounts, email subscribers and blog as well.
Create a google+ account/page for your channel and share your video on google+. Join communities that are related to your niche and post your videos but don't spam, engage with the community and offer value. Add people in your circles and most will return the favor and if they see you also have a channel they will watch your videos and even subscribe.
These days, most of my youtube subscribers come from google+, it's really easy to promote your channel on google plus.
Look for forums that are related to your niche, most forums will allow you to create a thread and embed your video with a short article explaining what your video is all about. But don't abuse this, do this maybe once in a month because forums hate self promotion and never promote anything just offer value and let the forum members decide whether they want more from you or not.
Join facebook groups, you can also look for skype and linkedin groups as well. Engage in those communities and post your videos once in a while.
Join the youtube community, youtube itself has a large community. For everyone who subscribes to your channel, go to their channel and post a comment in the discussions to thank them for subscribing. This is a free backlink and most people who visit those channels may see your comment and visit your channel as well.
If they respond to your comment or like it, it will show up in their activities so everyone who subscribed to their channel will see that and might check out your channel.
If you have a schedule for uploading your videos then let them know on each video when you're going to upload the next and tell them to subscribe so that they don't miss out...
Contact other video creators in your niche to find out if they can be able to feature your channel on theirs and tell them you'll do the same. But the best way is to add their channel first and let them know you have their channel featured on yours then ask them to return the favor. If they don't respond you simply remove their channel and move on to the next guy.
Collaboration videos are becoming popular on youtube, whereby you exchange videos, more like guest blogging. Find people who're interested in collaborations and if your videos offer a lot of value then most people will say yes to your offer.
Don't spam by promoting your business each and every minute of the video, offer value and promote yourself at the end of the video and add a small call to action. But respect other people's channels and audience.
Most importantly, track your stats so that you can be able to see where you need to spend your time and effort to improve your channel. Hope that helps