Here’s a suggestion: do a search for “blackjack”, “online blackjack”, “cheat at blackjack”, “blackjack cheating”, “how to count cards”, “blackjack strategy”, “blackjack odds”, etc.
Look at the sites with good quality, solid, useful content. Look at the sites that are banner farms. Decide for yourself which ones are which.
Look at the keywords they’re targeting–you can usually tell because they’re in the title tags of each pages.
Use the sites you like and the content you like as role models for your site. But don’t copy or steal content.
Then find a need or a niche that neither the good sites or the bad sites fill. Make sure it’s something that you’re confident that you can handle.
After that, the real work begins.