Thank you for your comment!
I am not a very good teacher. I just do my routine when analysing for patterns and EW, that I have trained over the years. I am not even certain if this is the most effective way to do it.
You can try to comprehend my counts and counts of other people. I recommend watching every video of @heajin, because he explains his counts in great detail.
Then you need some additional theory. You need to know what the three most common standard corrections look like and you need to know about extending waves and that wave 3 can never be the shortest.
Practise makes perfect.