I always sucked at this too, especially in unfamiliar airports.
Fortunately for you, if you fly out of a towered airport often enough, you can take some time to learn where the taxiways are by studying a diagram. You don't have to know all of them, just the main ones (Alpha, Charlie, depends what their main ones are).
If you really want to get it right; what does a paper copy cost these days? I'm serious, I have no idea; my point being, if you can make some copies of the airport diagram, you can mark them up while he's giving you instructions. So before you call up, find where you are on the diagram. You already listened to ATIS or the AWOS or whatever you kids are listening to these days, so you know what the active runway is.
Try to guess where they'll take you, but be warned your guess might be wrong. Get your highlighter clicked and ready; now call up and say "I'm here, with information <whatever>, request taxi to the active, westbound departure" or wherever you're going.
He'll say "Roger, taxi via alpha, alpha 2, charlie, foxtrot, echo, blah blah blah". Take your highlighter and try to mark up where to go, it should at least kind of make sense.
Another way, is just to not think, and just write down what he says as fast as you can write, no thinking, just writing. Alpha, Alpha 2, Charlie comes out as:
A
A2
C
...etc, on your kneeboard.
Listen to tons of Live ATC (liveatc.net). Also, in your spare time, sign up for one of those simulator worlds where you talk to people. I used VATSIM, Minnesota had a great tower/approach/center crew for a long time, don't know what the status is now. Otherwise there's a pay one that gets good reviews, PilotEdge.
https://www.pilotedge.net/
Safe journeys!