Anything on YouTube needs to be engaging, and you need to be using CTA known as "call to action" buttons. these CTA buttons are things that will lead people someone, i.e an annotation suggesting a similar video, or the new "card" feature that YouTube introduced. not knowing your channel or what it looks like i can't really give you exact tips but rather a general overview of growing.
Myself, i do gaming. I have been on YouTube for a year and a half now and have 17k subs and 2.2 million views, this was all done over time with engaging content.
You have to be consistent,i noticed more people subscribed when i uploads regularly, it was about 1/2 times a week now I'm uploading about 5 times a week.
Have nice laid out channel, and i mean the homepage of your channel with playlists, uploads etc, not the default stream that just goes straight down. People look for professionalism now adays in channels, a banner and good profile picture can sort that. Link any social media like facebook, twitter, soundcloud showing off your work and maybe your website?
Engage, if you are using twitter re tweet anyone who likes your videos, make sure you have your twittet linked to the YouTube so it says "example liked *name of video* by @example" then you will get a notification you can retweet. Be sure to comment back to people who comment on your YouTube, it reminds the viewers that they are actually noticed and you engage.
Tagging, titles, keyword? make sure it is SEO friendly, this is using specific keywords and trying to get your video ranked by being accurate as possible.
learn, from your most viewed videos and maybe create content based on that.
CTA, add an annotation to subscribe, maybe a card to your previous video, something like that. It;s also good to share them to facebook, twitter etc as you say. don't spam your channel to pages you'll get a bad rep for it and probably dislikes, it's best to share it maybe on your timeline or to your own page spamming the link isn't going to be effective, people finding you "organically" is what you want, this can be achieved through optimizing your content, using key words and making engaging content, the longer a video is watched the better it gets ranked.
Have you tried approaching people with it, maybe a collab? You offer them X and they eventually bring you subs, this could be song you have made approah a YouTuber to use it or something and then they give you credit and then they'll see your tutorial on it, but with what you do it might not be the best to collab. Offer free music though if you have mad some songs with fruity loops, then link your guides on how to do it to them? Maybe type into google and search for people having troubles with guides you might have on your channel.
Anything like that helps :) Hope it helps you out a little :D remember if you posting quality content and having fun then sub count is just a number, it's always great to have an audience who all watch your videos and are active :D