This article is not about learning to count cards. I have a separate article describing the learning process for counting cards you can read here: Learn to Count Cards.
Once you've practiced and you think you've mastered counting cards, you need to think about how to actually put your new skill into practice. Many new players make the mistake of beginning their count with each player's first card. This makes card counting harder than it has to be.
Instead, wait until each player gets his second card. Since many two card combinations will cancel each other out, you'll be able to count fewer cards in order to keep a running count.