I think Randy’s suggestion to make it a “how to play blackjack so well you’ll feel like you’re cheating” is excellent.
There are many resources for this, too.
I have stacks of books on poker, and I’m putting together a poker site that may make a winner even out of me! There are even more books on blackjack available. Try amazon.com. There are also a huge number of blackjack sites, which may help you narrow down your focus – it’s easy to bite off too big a chunk at first.
Most importantly: Be a blackjack player. Play the games – play all the versions of blackjack so that you’re writing about something you know – it’ll make a difference. Play for free and for real money. I know it’s a drag, but someone has to do it.
:p