All the stuff about SEO and viewing your site like a search engine is great advice and extremely valid. But I think you need to step back a bit, think like a visitor to your site and ask yourself the question:
What does this site do uniquely and/or better than any other?
To be honest (I hope you appreciate I’m only replying because you said you were getting disheartened and you seem like an earnest kind of bloke) I find it hard to answer that question.
A well-optimised site is vital but unless you have a unique value proposition, it’s a bit pointless.
Site visitors are very fickle. If they don’t ‘get’ your site very quickly, they’ll go back to Google and find another site from the hundreds of thousands of search results.
Some well-established sites wouldn’t get off the ground if they started now. Don’t be tempted to copy them. Think of something new and original, focus on it and do it really well. As we’ve discussed before, Jackpot Graphs is a top idea, but it’s essentially just a new way of presenting the same information other sites do. There are other ideas out there. We just have to find them.
Keep plugging away. The best advice I’ve been given is that you have to allow 18-24 months to get established. You’re only half way there!