You hear often enough that practicing blackjack and blackjack strategy will improve you blackjack game and skills. This is very true. The only way you become better at something is to do it.
This truly applies to card counting when you are first learning the skill. Card counting, while it can greatly benefit your blackjack odds and your profits, it does require a lot of practice and time to make the skill a profitable one.
This is especially important if math is not your strong point. Even the most basic counting system, Hi Lo, involves adding positive and negative numbers together in your head quietly and quickly. It is important for you to be able to do your math in your head quickly and quietly with no outward appearance of doing so.
It is just as important as making sure to vary your wagers a bit when counting cards. Casino staff will watch players