You have so many potential income streams, don't limit yourself.
- If you've not already done so, you should be working on trying to funnel those visitors to any of your social accounts (I'd suggest IG mainly). That in itself will open up it's own set of potential revenue opportunities. Work on your sites optimization and your content to ensure people click through and follow you on your socials and stay on your site longer. This along with a lower bounce rate will give you better ad rates through ad networks.
- Turn your site into a brand, brands sell, 'pages' don't. Just by doing that you could easily approach companies or individuals in your niche or similar niche and try sell them an ad spot on your site. Create a gfx infographic of your sites stats to help with selling spots, presentation is everything after all.
- You mentioned you tried selling products/affiliate marketing. You need to work on 'warming up' leads, work on your landing pages & optimize them, don't give up because it didn't work out the first time. Switch up products, use the urgency sales tactic, talk to whoever you're an affiliate for and see if they can help you, and most importantly for this, it's all about testing...
Looking forward to seeing how you get on. If the response from this thread isn't motivation about the $$$ you're sitting on, this should be one -
The monthly page views is around 500,000 and the traffic is mainly coming from United State.
500,000. Mainly United States. Those are your words. And more importantly, one of the highest avg CPC/CPM countries.
It won't be easy, you still have work to do. But hey, you made it this far! Go get that $$$