“I don’t plan, I do” Write design documents. Communicate in writing your plans to align expectations.
“Using the wrong people for guidance” Search for 3–4 mentors. Always use your judgement when taking advices.
“Linkedin and GitHub are for seniors” No they are not only for seniors, but for juniors as well. Invest in your personal brand and utilize popular professional social networks.
“Focus on the code, not on the system design” Understand the context. See the bigger picture, not only on the task at hand.
“Stackoverflow is better than the docs” Don’t be lazy. Understand the core, the “why”, the DNA of the tools you use. “Reading the docs” can be the perfect simple source of knowledge you need.
“I am a tech professional first, and a team member last” Be your team lead’s right hand. Teach. Listen. Document. Show respect. Be open minded. Foster good relationships. Care about being a good team member. Work with people, not only with the code.