In my experience:

1. read a lot. Design patterns, architectural patterns, microservices patterns. There are good material out there

2. apply what you have read in your day to day job

3. stick with a job for more than 2 or 3 years

Points 1 and 2 are obvious. Point 3 is necessary: if you are jumping from job to job every 1 or 2 years you'll never experiment how good (or bad) your"architectural" solutions are. People usually jump into a new job, implement all the cool patterns they have read and then after 1 or 2 years they leave the company. So you never learn to judge your own solutions because the moment your solutions need to be maintained/extended, you are leaving.