Anxiety doesn't necessarily cause concentration problems as its own symptom. In fact, it could be argued that anxiety actually improves concentration. Anxiety is the activation of your fight or flight system, which is meant to keep you safe from harm by ensuring you're running away or fighting without distraction.
The first set up is a standard 20-25 pound test rig (depending on the size of the tuna) with a size 1 to 2/0 hook depending on bait size and the size of the tuna. Fluorocarbon leader can be super effective if the fish are touchy (biting infrequently). This set up will be the primary bait fishing set up.
A part of enjoying them, you do need to know what type of bait, fishing equipment and even size hooks to bring with you. Perhaps the best advice to give someone who is fishing for big game fish such as yellow fin tuna is to judge the hook size more according to the bait size than the fish size. Your target fish will determine whether you need small or large bait.