It might be one of those games that takes a while to develop a strategy for, and maybe that’s what’s missing that keeps you from visualizing the concept. Maybe the more you play, the more you’ll get a feel for how certain decisions can play out and help/hurt your overall play? And the more the game will develop a structure in your mind, rather than just being a series of rules to follow… But right now, as it’s new, you haven’t developed that strategy-knowledge yet?
So, for example, imagine you’re learning checkers for the first time (I don’t know Ticket to Ride, so I’m just going with checkers for a simple example). You’ve got a bunch of checker pieces, and at least in this case the rules are pretty simple… But even with checkers, the first time you play, you’ll have no idea what strategy to apply. Which checkers piece to move first? What will the other player do next? How do you get to the other end? How do you keep the other player from taking your pieces? Oh, and wait, what happens when my checker gets to the opposite end again? And can I take that checker of yours, or is it not in the right position? And should I? ... But the more you play, the better sense you’d have for how to answer those kinds of questions.
So (I’m guessing) you just don’t know the strategy yet. You will. In the meantime, I’d probably just take a best guess each turn and see how things work out (and if it didn’t work, then make a mental note and try something different in the next round.) Also try asking your friends questions like, “Why did you do x and not y?” and see if they have an explanation for you.
Maybe that will help?