One of the advantages to play online live blackjack is that no one sees you - so you can give card counting a shot. This said, counting cards in blackjack online isn't easy. Live dealer blackjack don't give you enough deck penetration to be truly accurate with card counting as (in most games) the cards go back to the shuffling machine after every hand.
You find more about card counting and your blackjack strategy on this article. In general, you should not rely on card counting as your sole blackjack strategy.