Counting is a tough (and oft-ask about) topic.
It takes years of experience to be able to do this well.
This article is meant only to get you started with counting.
We will talk about counting only one suit. (Counting out an entire hand takes tons of concentration, and at least 10 years of serious play.)
Here is the main message: Think in terms of what is missing.
This is the opposite of the "1-2-3-4" approach. Most new players