Just can't get traction on Facebook

Hello,

I have been busy with IM for a while now (about 8 months) running one site sharing pictures on social media and driving traffic to the site, and making money with AdSense ads. I have 3 main facebook pages (Jokes, Motivational Images and Scenery)

I am getting about 20,000 unique visitors a month to the site, but that is mainly from pinterest. I have developed my own bots to post to the social platforms and they seem to be working well. 65% of all traffic is mobile users. AdSense earnings is about $300 per month now.

But for the love of me I just can't cut it on Facebook. The fan pages just does not want to grow, I do the odd promoted post, and then gain the odd 10 fans, but at that pace it will take me 100 years to get a good base.

My Questions:

1. Is there a good way of getting website traffic (mobile & desktop) users to like my pages?
2. Should I invest all my adsense earnings into buying fans on facebook? Is it worth it in the long run?

Thanks and thanks in advance for anyone willing to share a secret or 10

Post content that will engage your users into liking, commenting, and sharing. Images that evoke emotion or require the user to engage are pretty useful. Can't just promote any old post and expect it to do well. Network with other high quality pages and trade shoutouts or something too.

I really think my content is good, If I compare my interaction percentages then it looks good compared to other bigger fan pages, but I just don't get new fans. I am based in South Africa, and the weird part is that my most active country in South Africa, and I just can't get any international fans.

I have tried to network with other pages, but they just ignore me. I have 500 fans, so it's REALLY small. Any tips on Networking?

The same content performs very well on Pinterest & G+ and based on my traffic I must be doing something right, but just not on Facebook.