Context: I worked as a team lead. I had technical and also disciplinary responsibility.

How do you get that next level in your career, how do you loose that "junior" title? And I don't mean how to get the next pay raise.

In my own experience as a developer, and with junior devs in my team, its pretty easy as soon as you understand what to focus on.

To get to that next level, your learning target changes. At the beginning of your career your learning targets are all technical things. First you need to learn a programming language, control structures, what variables are and so on. All that basic stuff you need to get the job done at all. This is actually pretty easy and fast.

What now? You are working in a team, you get your tasks done. Hopefully your code gets reviewed and you learn from that. Also hopefully you can review the code of others and learn from that. what would you learn next? Maybe to gain more knowledge about your persistence framework or the database. Maybe it would be good to get some more details about the programming language or its base framework. Or what about that REST or SOAP or Protobuf?

One step back. What was the last feature you implemented? Did you fully understood what you did and especially why you did it? What benefit did it bring? What users will gain benefit from it? Was there an alternative? And if so, why wasn't it chosen?

Short: Learn to first fully understand what the feature at hand is for. Ask, ask, ask. Don't start work until you fully understand what value this feature brings and to whom. As soon as you know that, you can try to add even more value with making suggestions on how to improve that feature or try cut costs by discussing why this feature is implemented in the first place. If you reach that point and your code is on a decent level, your days as a junior are over.