As I'm only starting to learn the trade this is something I'm feeling my way around. Knowing when it's a nailed on yellow I'm finding easy, it's the ones that perhaps come as part of 'game management' and the consequences of giving or not giving it.
I guess you learn from your mistakes here and I reckon it's different for every ref/player/team/division/league....
If you getting the nailed on ones, thats a good start
the others, by definition, because they are not nailed on, are really down to the ref on the day, the tempo of match, the time, the consistency with whats gone before, the surprise or lack of, element, the player himself, is he drawing attention to himself, is he the quiet placid winger and a purely isolated occurance, do you know the players, can you manage him, might the other team seek their own revenge, whats the score, and on and on,
am sure I have even used the weather! guy kicking ball away or trying jump in front of a quick fk, a sinple, " look its a miserable enough day without you getting booked for that"
its never going to be an exact science. And of course we dont have a crystal ball. Until we are at a place where we truly trust ourselves, imo, leaning to the card, rather than away from it, is the better option. Safe refereeing. So what if in each game a soft yellow comes out. We have enough to do, positioning, running, looking at offsides etc, trying to be too clever on the managment side just adds to the task