Blackjack with a single deck would be the one game where the card counting techniques would pay off, and pay off really nice. It does come with certain difficulties, however it can also offer the most accurate results if done properly. The main difficulties with single deck blackjack card counting are caused by the fact that several cards will remain face down up until a certain moment of the game (like when a dealer hits the blackjack, for instance) and then all of a sudden they will be revealed all at once and a player would have to add them all up. It is quite difficult, and requires a good deal of learning and training.
You can rely on special online trainers for practicing single deck blackjack strategy, but also you can do just with a regular deck of cards at home. Actually the more cards the better for the process, but start with just one. While you are going through the deck mentally add up and subtract the values of the cards that you see, gradually increasing the speed. Don’t get discouraged if you will be taking too much time at the beginning. Over some time your brain will get to the needed frame of thought.