After several months, I am back implementing HTML components, entailing coding CSS elements as well. To be honest, even though I master the subject, I've forgotten the advanced tips and tricks. But as a Software Developer, we often find ourselves in this situation, especially when changing teams, projects and/or companies.
The first thing I do is to search for the technology + cheatsheet and/0r cookbook on Google. I glance at most concepts just to refresh my mind. The main idea is to avoid making elementary mistakes which beginners usually do (and I've myself done plenty of times).
I also try reading crash courses or watching videos for the same reason whenever time permits.
Moreover, once I've coded a solution, I talk with another senior developer to confirm if the way I've implemented the codes is the right way to do so. Or, I can directly create a Pull Request, with which, I get the feedback required.
A good thing to note is that different teams for different projects might have separate conventions even for the similar technologies. One team might use CSS for a project, while use SCSS for another. Therefore, the idea is to get actionable feedback to progress in the right direction.
An interesting website that always help to remember concepts of a particular technology is learnxinyminutes:
For me the most important part is to be productive, yet making sure that I am at least writing quality codes.