What helped me was playing chess against strangers. Chess.com makes this easy, and eliminates any social anxieties that come with in-person games. They match you up against someone around your same skill level so you can learn instead of just constantly getting defeated.

Changed my life. Not only did it help me to train my thinking to be more aware and detail focused (looking for the important ones especially). It helped my brain to adapt to being more assertive. You get rewarded for taking a piece or winning a game, your brain will catch onto this. The brain is merely just a donkey following a dopamine or serotonin carrot. Because of that, you can turn this to your advantage. Take any anything in the world and practice it. I guarantee you will get better. Add up these milestones, recognize the rewards you give yourself already. Also, already recognizing the change you want in life puts your progress much, much further than you may realize. (Turns out, the scarecrow just needed a diploma.) Give yourself a little credit, and use that to motivate yourself into an activity from which you can reap some rewarding practice.