If you're just starting put out one or two videos and send them around forums such as this, asking for what they think of content/audio/visual quality, if they say it needs improving - then improve on it, if generally people say it's good, then just keep releasing videos as frequently as you can - and hopefully one will draw that audience in.
generally to be a partner the minimal requirement is 750+ video views a day and you can use
www.socialblade.com to see if you're getting this.
Also linking your videos together using annotations is proven to increase overall video views by around 15%, so that would help you get those views required to be a partner.
In extreme cases, if your content is VERY good, and you apply without partner network criteria, then they can still offer you partnership, but my advice is to wait until you have the proper requirements and then apply.
Good luck!