I would imagine that sharing on Social Media would be the first place to start.
Thanks, definitely done that already. Looking at more avenues. Can't even find a good subreddit to post in to be honest.
yt + ig are the best starting places in my opinion. There are many threads here on how to grow yt channel and ig account.
Also, you can combine commenting strategy in related forums and blogs to grow your audience.
Look at where other similar channels post, I would imagine that Instagram and Pinterest might be good options. Check FB groups, there must be a few that deal with make up.
Like @mousepotato mentioned, Pinterest might be worth a go also @Vadevious. I would definitely recommend making a separate image that advertises your video, as the default image that you get as a result of your link might be the video thumbnail which will be of low quality (example here of a design). Mix your boards with other people's content also, there's no conclusive evidence, but I've followed that and it seems like Pinterest are more willing to put your pins and boards out there for others to see when you do this.