Right now, I'm upgrading my Nushell plugin in Rust code while not being very familiar with Rust and its mechanisms. I'm using the build errors, cargo crate (libraries) documentation, auto completions/suggestions, existing own and cate/lib source code to find the correct methods and way to do data format transformations. I managed to make it compile again, so now I'll test-run it. I "accidentally" extended what it can map as well, which is a positive side-effect.

It depends very much on the role I'm in, and what you're asking in particular. As far as hands-on development work,

• No, I don't copy tons of code
• I read and/or search and/or analyze and/or remember existing code, to understand what is happening, identify bugs, or embed and write solutions that make sense within the project, reuse existing mechanisms and approaches
• I develop and write solutions, sometimes in one iteration, sometimes through multiple iterations, when I have new findings during development or solution behavior or new questions raised
• When it's web, it's more writing, if it's a Windows Forms app developed with Visual Studio, UI placement and layout is a UI process, but connecting it to and implementing it's logic and behavior is still a coding task
• I love making use of efficient editor and IDE features like multi-cursor editing when they're useful
• Overall, I think being in the UI is the smaller part of development

Professional development in general entails much more. I work with my customer and consider their workflows, needs, I discuss and question their requirements, I design solutions both in user workflow, UI, UX as well as in code architecture and implementation. For a long-running project, improving existing code is a large part of what I do when implementing new changes. Documenting what I find out or see and is not documented yet is another big part.

If you feel you never get it beyond absolute basics I encourage you to work on tools, utils, or projects that you use or care about. I wrote various utils for my own benefit and use, and do regular drive-by contributions to projects I find useful or interesting (mostly related to documentation or tech approachable to me).

Don't just follow tutorials. Set a goal of something that works. Be it a clock, a calculator, a command line tool that let's you read music file metadata, or starts or stops programs for you. Or whatever you feel might be reasonable to explore and achieve, whether with or without practical use.