What you have to learn is to score reliably when on offense, in such a way that you score the touchdown at the last turn (by stalling). So, that (unless your opponent does a one-turn touchdown, which is possible vs. the disgusting rats) when the second half starts and your opponent is on the offense now, you are leading 1:0.
In this position, vs. slower teams, as elves, you can slow them down from scoring altogether, but vs other fast teams like other elves or skaven, you want them to score quickly. So, accept that they will score just make them score quickly so you can have as many turns as possible to score when you get on the offensive again, and then you would win 2:1.
I wish I had a more systemic way of thinking about the game
There was some 'turn order' I remember reading about on bbtactics or some other site, but I can't find it anywhere now...
It was something like:
1. first make sure to do least risky (no dice) plays, e.g. get your guys up etc.
2. then, when you have to do risky plays, do the most important ones first
How do you know which plays are most important ones? If you're on the offense: securing the ball (placing as many players around the ball so it's more difficult for the opponent to pick it up himself), protecting the ball carrier, making sure opponent doesn't get to blitz/block your ball carrier, or scoring.
If you're on the defense: making the opposing ball carrier uncomfortable (like you're doing in that first screenshot), but also afterwards doing the screen properly. Make sure to not base too much (as you're playing elves), although this all depends on the situation.
With blood bowl it's really the more you play, the better you get at it eventually, and the learning curve is steep. I take a break from blood bowl once in a while (like right now), cause it's a frustrating game to play sometimes. IMO it's too random, in a sort of unpleasant way, I wish they designed it differently. RNG in something like Wesnoth is a lot better...
We could do a Codex Wesnoth tournament, that could be fun.